I've purchased old nikon ais lens on ebay. It was really cheap. Turns out it has some fungus growing inside. No worries, I take apart and clean. I used rubbing alcohol, 98% solution to clean it. Turns out it stripped some of the coating. I tried to clean with solution for glasses. But it leaves smudges and is not perfectly clean. Before I ruin another glass element, what solution is recommended for this use?
The coating was probably already damaged by the fungus, not the alcohol. Though you should consider using a lower concentration (70-90%) like a normal person.
PetaPixel: How to Remove Fungus from a Lens describes removing fungus by soaking the affected elements in an aqueous solution containing hydrogen peroxide and ammonia. After the fungus has been removed, the lens elements can be rinsed in distilled water and dried with a lint-free cloth before reassembly.
Some hints from someone who dabbled in it:
-Invest in some actually dust and lint free paper towels for drying things. It's good for your sanity.
-Contact lens lifters are very helpful in handling elements - but they tend to leave residue too.
-Alcohol-based (NOT soap based) eyeglass wipes aren't THAT bad if we aren't talking expensive or pristine lenses.
-You will need to clean multiple times to get all residues off.
-Make sure any particles of metal, glass, or stone are gone before doing any wiping on a glass element. They scratch everything to oblivion. Especially evil: metal filings clinging on or hiding in crevices after you had to drill or file to be able to attach a lens opener. Any cloth, q tip, wipe that potentially got contaminated with such particles you throw away.