When cleaning a lens with peroxide/ammonia fails, what else?

[Brian Atherton]

For the past thirty-plus years for general cleaning of optics when they're really messed up I've used Rosco - but sparingly as it's mostly the UV filter on my lenses that gets dirty.

The new multi-coatings that dispel fingerprints and water (such as B+W's MRC nano-coating) definitely make life easier and need far less cleaning.

http://www.rosco.com/FTVP/lenscleaners.cfm?menuReturn=film

 

[johnnyrod]

Ammonia and peroxide seems to be the de facto way of removing fungus, and it does work. Alkaline things clean glass well. If ROR is that good then I'm gonna give it a go next time I think.

Simply using methanol is pretty good at shifting most things though. I think some SLR lenses have silicone lube in them, for which you need a straight hydrocarbon like Ronsol/hexane etc. which is 100% non-polar or lyophilic/hydrophobic/choose your term. It's not easy to dodge some of the technical content on this, but simply put, like dissolves like. Methanol is fairly polar/hydrophilic, ethanol less so, isopropanol not that much at all and so the best for grease, but not as good as Ronsol etc. because it's even less polar.