When I bought a bulk bundle of microfiber glass-cleaning cloths once, the instructions that came with it said to not use any detergent or soap, that it would tend to stick to the cloth and make things worse rather than better. The suggestion was lots of clean hot water, and that oils would not stick to the cloth, would be washed completely out. I have been doing that, throwing a few in a mason jar with hot water, and shaking a lot, several cycles of water, only, for about the last five years with complete success and zero streaky lenses.
I want to stress that this advice did not come from an anonymous amateur source on some website, which invariably say to use a bit off soap---it came directly from the manufacturer. .
Here's what Hoya, a manufacturer, says, 3 options, one of which is just to shake the cloth around in the air and maybe the dirt falls away. Prayer facilitates this. Or hand wash it. Or wash it in the washing machine. These suggestions from the manufacturer are ordered, if I might guess, in order of effectiveness.. But, whatever.
http://blog.hoyavision.com/spectacle-wearers/how-to-clean-your-micro-fiber-eye-glass-cloth
Hand washing is for delicate things like frilly women's undergarments (do they still wear those?). There is nothing delicate about a microfiber cloth. Just nuke it already.
If your shirt got dirty where would you wash it? In the sink, or in the washing machine? Over and above the bother of trying to do it in the sink, you'd most likely put in the washing machine. Why? Because you and everybody else knows it would get cleaner that way. As it would. And more likely to get all the detergent completely rinsed out as well.
Hot or at least very warm water because that gets the oil out; they don't shrink. If you are traveling, sure wash them in the sink, but if you want to be sure something is completely clean and dust grit free, and thoroughly rinsed, put it in the washing machine. Not only the easiest, but the best, how often do those two things go together?
Or, just wave your dirty one around in the air for a bit, then rub that Noctilux with it. Manufacturer recommended, not some anonymous amateur on the web.
🙂
But being happy with what one has been doing, that's the main thing, I suppose.