Thymol for killing mould

[Roger Hicks]

An old friend died a few months ago and I am now helping his daughter to get rid of a LOT of gear. Much of it is in appalling condition and some of the older lenses are mildewed. I have read that placing stuff in a box with thymol crystals can kill the spores. Has anyone tried this? How long for? Any adverse effects? (Unless you don't like the smell of thyme).

Fortunately it's not all mouldy: some Leicas, Leica lenses and Leica finders...

There's also some SERIOUSLY rare stuff, such an AYOOC finder and a lens cap for a 50/2 TTH/Reid. She was quite surprised when I found that the latter go for $150-250 (though this one is a bit ratty, so probably $100-150 to a user) and that the only AYOOC chest level finder on sale was well over $500.

Cheers,

R.

 

[Livesteamer]

Don't know about thymol but doesn't exposure to UV light stop mold? Strong sunlight if nothing else.

Good Luck, Joe

Sorry to hear of the loss of an old friend.

 

[sevo]

Thymol is an antiseptic, but it also is a very capable solvent and softener - it might mobilise grease, strip paint and adhesives and soften plastics (Listerine spills once ate through my plastics bathroom cupboard). I would not subject entire lenses or cameras to it, at least not without prior tests.

 

[DominikDUK]

The smithsonian has a nice site about textile restoration and mould removal
https://www.si.edu/mci/english/learn_more/taking_care/mnm.html
The canadian conservation Institute Removing Mould from Leather – Canadian Conservation Institute (CCI) Notes 8/1
http://canada.pch.gc.ca/eng/1472055630810

Good luck

 

[Highway 61]

If there is something visible in the optics already, you're beyond the spores stage : there are mycelium filaments having grown up (call it mould, fungus, whatever, and it has different types, benign, acid, etc) on the optics surfaces and probably elsewhere.

Only a proper cleaning requiring that the mycelium material will be wiped off then the optics sterilized before reassembly will do it. In case of some acid fungus, the optics may remain affected forever with something looking like some very fine internal scratches.

Spores stage : prophylaxis (don't keep any photo stuff in their leather cases, keep your photo stuff in some dry areas, allow the air to be renewed, don't lock your photo stuff in total darkness, allow some dry ambiant air enough to surround your gear, never store your photo gear altogether with something prompt to trap humidity, etc).

Mycelium stage : typical remedy.

No other way. Killing visible mould/fungus with some chemicals vapors or UV exposure (and then, getting the sick items clean again) without any actual surface cleaning is another popular hoax.

 

[johnf04]

I tried killing (and dispersing) mould in a lens by shining a UV torch in it, for a month. There was no obvious effect.

 

[andrewmore]

Moulds can and are killed by UV-C (used in conservation settings amongst other things). I know this as I’ve built two rigs for that purpose and advised on a third and have contributed to a paper on the matter and am mentioned in another (I’m a Chartered Engineer specializing in Building Services in Historic Environments). UV-C however can be filtered by certain types of glass and so shining it through a lens to kill mould growing inside the lens may not be effective in all cases - you would have to test each type of lens glass to see which lets UV-C through and which doesn’t and aren’t some lenses a mixture of glasses? Dismantling a mould affected lens where the mould is inside the construction for treatment would be the only way forward I fear…

Regards

Andrew More

 

[ChrisLivsey]

I have no experience of treating fungal infections of lenses with Thymol but it is shown to be effective on toenails:
Ramsewak RS, Nair MG, Stommel M, Selanders L (2003). In vitro antagonistic activity of monoterpenes and their mixtures against toe nail fungus pathogens. Phytother Res.;17(4):376-79
:angel:

 

[johnf04]

Unfortunately, the front elements of the lens I treated are in a sealed block, and the mould is inside.

 

[Peter de Waal]

We have a lot of problems in New Zealand with moulds and fungus due to high humidity levels and generally poor housing insulation/ventilation. Some glasses are much more susceptible - like the modern LD types (i.e. Nikon AI-s) which are softer and etch badly.

To really fix an infected lens it is necessary to completely strip the lens, remove all paint including edge blacking on elements and re-coat with a paint containing a fungicide. Cleaning the glass only temporarily fixes the problem, although if stored in a very dry room it will not progress too quickly...

Here is a summation of WWII research for treating instruments used in jungle campaigns, convoy warfare, etc. from:

http://www.europa.com/~telscope/fungus.txt

The summary:

Many old optical instruments have fungus growth on a glass surface. Fungus does not look like haze but has an appearance like hairs or tendrils branching from a center. While the fungus can be removed by cleaning, it frequently has etched the glass, since fungi secrete enzymes and acids to chemically alter their environment so they can absorb nutrients. This etching requires repolishing, which if done unprofessionally will ruin the instrument. It is not possible to tell if the glass is etched until the fungus is cleaned.
Maintenance of optical instruments involves prevention of future fungus problems, especially if located in damp regions.
To sum up the lengthy documentation below:
--WWII research programs on fungus in optical instruments (Turner, below) used sodium ethylmercurithiosalicylate, now known as Thimerosal and widely used consumer medical products. When mixed in paint used inside the binocular, this was found effective at preventing fungus. It is not known if Thimerosal is so
used today.
--Hydrogen peroxide, or bleach, can be used to kill fungus.
--Leitz documents describe a fungus treatment of 94% distilled water, 4% clear
ammonia (for cleansing) and 2% hydrogen peroxide (to kill fungus).
--Carl Zeiss Oberkochen, dept. KuDi, sells: Fungus Cleaning Agent
"Fungusreiniger NEU". Dilute with ethyl alchohol, leave on glass for one hour or
more, then clean. Not poisonous but avoid contact with skin. 100ml bottle, INR
0117.362 500ml bottle, INR 0117.361 1000ml bottle, INR 0117.360
--Notes on treatment & prevention are found at the end of this text.

 

[phofseth]

And in Norwegian folk tales, rubbing your sheep with thyme kept the trolls away.

Probably not available anymore in an English translation, no market: trolls used to have their heads chopped off, so these days such stories may be supressed as unsuitable for children.

An outfit in Luton did a spendid job removing mould on one of my lenses.

p.

 

[Roger Hicks]

Thymol is an antiseptic, but it also is a very capable solvent and softener - it might mobilise grease, strip paint and adhesives and soften plastics (Listerine spills once ate through my plastics bathroom cupboard). I would not subject entire lenses or cameras to it, at least not without prior tests.

Well, I'm not planning on smearing it over the cameras: just subjecting them to the vapour. The stuff sublimes, after all, and although it then recondenses, I'd have thought that in the quantities involved it shouldn't be a risk.

Cheers,

R.

 

[Roger Hicks]

Don't know about thymol but doesn't exposure to UV light stop mold? Strong sunlight if nothing else.

Good Luck, Joe

Sorry to hear of the loss of an old friend.

Thanks for the condolences. Yes, UV works very well, but my understanding is that it merely inactivates the mould: it doesn't kill the spores. I'm hoping that thymol might. I know that the spores are pretty much everywhere and can re-infect the cameras and lenses but if there are no disadvantages it strikes me as worth trying.

Cheers,

R.

 

[Roger Hicks]

The smithsonian has a nice site about textile restoration and mould removal
https://www.si.edu/mci/english/learn_more/taking_care/mnm.html
The canadian conservation Institute Removing Mould from Leather – Canadian Conservation Institute (CCI) Notes 8/1
http://canada.pch.gc.ca/eng/1472055630810

Good luck

Thanks. This is easily the most useful answer to my question. Even though it doesn't directly address cameras, it's a good start.

Cheers,

R.

 

[Roger Hicks]

I tried killing (and dispersing) mould in a lens by shining a UV torch in it, for a month. There was no obvious effect.

Dear John,

No, there normally wouldn't be. Mechanical removal is normally essential, though if there are only a few tiny spots the UV treatment can make them go away. I know this because the same friend who died once tried this on his 50/1.

Cheers,

R.

 

[Roger Hicks]

We have a lot of problems in New Zealand with moulds and fungus due to high humidity levels and generally poor housing insulation/ventilation. Some glasses are much more susceptible - like the modern LD types (i.e. Nikon AI-s) which are softer and etch badly.

To really fix an infected lens it is necessary to completely strip the lens, remove all paint including edge blacking on elements and re-coat with a paint containing a fungicide. Cleaning the glass only temporarily fixes the problem, although if stored in a very dry room it will not progress too quickly...

Here is a summation of WWII research for treating instruments used in jungle campaigns, convoy warfare, etc. from:

http://www.europa.com/~telscope/fungus.txt

The summary:

Many old optical instruments have fungus growth on a glass surface. Fungus does not look like haze but has an appearance like hairs or tendrils branching from a center. While the fungus can be removed by cleaning, it frequently has etched the glass, since fungi secrete enzymes and acids to chemically alter their environment so they can absorb nutrients. This etching requires repolishing, which if done unprofessionally will ruin the instrument. It is not possible to tell if the glass is etched until the fungus is cleaned.
Maintenance of optical instruments involves prevention of future fungus problems, especially if located in damp regions.
To sum up the lengthy documentation below:
--WWII research programs on fungus in optical instruments (Turner, below) used sodium ethylmercurithiosalicylate, now known as Thimerosal and widely used consumer medical products. When mixed in paint used inside the binocular, this was found effective at preventing fungus. It is not known if Thimerosal is so
used today.
--Hydrogen peroxide, or bleach, can be used to kill fungus.
--Leitz documents describe a fungus treatment of 94% distilled water, 4% clear
ammonia (for cleansing) and 2% hydrogen peroxide (to kill fungus).
--Carl Zeiss Oberkochen, dept. KuDi, sells: Fungus Cleaning Agent
"Fungusreiniger NEU". Dilute with ethyl alchohol, leave on glass for one hour or
more, then clean. Not poisonous but avoid contact with skin. 100ml bottle, INR
0117.362 500ml bottle, INR 0117.361 1000ml bottle, INR 0117.360
--Notes on treatment & prevention are found at the end of this text.

Thanks for the links and information, though I'm not sure about "very dry". Humidity below about 20% (quite hard to achieve) is rarely recommended. My Dry Cabinet (by Wonderful!) maintains about 40%.

Cheers,

R.

 

[Roger Hicks]

If there is something visible in the optics already, you're beyond the spores stage : there are mycelium filaments having grown up (call it mould, fungus, whatever, and it has different types, benign, acid, etc) on the optics surfaces and probably elsewhere.

Only a proper cleaning requiring that the mycelium material will be wiped off then the optics sterilized before reassembly will do it. In case of some acid fungus, the optics may remain affected forever with something looking like some very fine internal scratches.

Spores stage : prophylaxis (don't keep any photo stuff in their leather cases, keep your photo stuff in some dry areas, allow the air to be renewed, don't lock your photo stuff in total darkness, allow some dry ambiant air enough to surround your gear, never store your photo gear altogether with something prompt to trap humidity, etc).

Mycelium stage : typical remedy.

No other way. Killing visible mould/fungus with some chemicals vapors or UV exposure (and then, getting the sick items clean again) without any actual surface cleaning is another popular hoax.

As Senggye died in November, prophylaxis is not an option.

I'm not expecting the thymol to clean the lens magically at a distance. I'm just wondering whether it will, in fact, kill the spores and whether anyone has ever tried this. And, if they have, whether there were any adverse effects.

Cheers,

R.

 

[Highway 61]

I'm not expecting the thymol to clean the lens magically at a distance. I'm just wondering whether it will, in fact, kill the spores and whether anyone has ever tried this.

🙄

Sorry but you have asked whether thymol vapors could kill the spores at a distance without any wiping process (requiring some total dismantle of the sick optics) :

I have read that placing stuff in a box with thymol crystals can kill the spores. Has anyone tried this? How long for?

You've got some answers enough, based on what you described as for the condition of the stuff suffering from live fungus and not spores (there are much more spores in your own house than around the old photo gear you want to get clean).

Now you can do what must/should/can be done (chose the right verb).

 

[sevo]

I'm not expecting the thymol to clean the lens magically at a distance. I'm just wondering whether it will, in fact, kill the spores

The main problem would be to get at everything up to the last spore. Thymol will not magically penetrate everything unless you bounce up the concentration to the point where it will eat into the adhesives and paints. Conservators even use vacuum chambers to get the poisons to the target.

Mechanical cleaning will be required in any case where the gear is fungus infested. And once you are inside, cleaning with an approved optics fungicide (e.g. Zeiss 102.527) seems a more prudent way to go about it. For lenses that are not infested, but which you merely suspect to be invisibly infected, plain dry storage will do - simply vacuum seal them along with a bag of silica. As long as the lenses are stored in hot and humid conditions, even a perfectly disinfected one will pick up spores from the environment within days.

 

[Brian Atherton]

Dear Roger,

I have no idea whether the following is of practical use to you, e.g for instance, without disassembly how would one be able to successfully penetrate to the inside of lenses to attack the mould?

With the caveat that I am no expert in mould removal, conservation or a chemist, I make the observation that the active ingredients in an over-the-counter mould and mildew remover (Astonish Mould & Mildew Remover) I use at home occasionally in the bathroom, washing machine and uPVC window frames is:

Tetrasodium phosphonoethane 1,2-dicarboxylate and hexasodium phosphonobutane-1,2,3,4-tetracarboxylate.

The above are marked as bleaches, safe for plastics, glass, ceramic tiles but not for aluminium, copper, brass, chrome etc.

Also, I make the observation that sometimes passing on a little knowledge can be a dangerous thing.

Lastly, have you thought of contacting the conservators at the Science Museum, London?

I wish you well.