You used to be able to buy the stuff in drugstores as “Nu-Skin” or something like that. Kind of a liquid Band-Aid. Nowadays, I just make it up myself by dissolving nitrocellulose in a mixture of ethanol and diethyl ether.

(2) has the best music, (3) is the scariest method (I would not even put sticky tape onto the lens of my cheap Z3).

Before starting, one should wash the hands to avoid smearing ones skin oils onto the lens.

One should be careful when buying isoprop: Until recently, it was sold as a mild, skin-friendly desinfectant, und this usage is now outlawed in Germany (and possibly elsewhere) because it is too mild (i.e. does not kill all germs), which in turn caused it to disappear from most shops. As a replacement, one often finds solutions of solid germ-killing substances in 70% isoprop, and the solids will remain as residues on the lens (i.e. the same problem as with denatured ethanol).

I did not try methanol – it is more polar, so it should be friendlier to plastics (this is not a problem by itself, but dissolved substances from the plastic parts might end up on the lens), but it might attack anorganic coatings on the lens itself – does anybody know something about this?

When washing lens cleaning cloth: Don’t use normal laundry detergents, and fabric softener is even worse (both will leave residues behind in the cloth). Water and sodium carbonate are sufficient – there are no major amounts of dirt to be washed out, and a lens cleaning cloth doesn’t need to smell like perfume or to glide gently along your skin anyway.