I use a variation of a recommended recipe
ammonia
hydrogen peroxide
I can never find ammonia (in the house) when I need it, so my recipe is:
Windex 50% mixture
3% off-the-shelf hydrogen peroxide (about 12.5% mixture)
isopropyl alcohol (about 12.5% mixture)
I have heard that Sparkle actually has some abrasive material in it, adn it is not ammonia-base, so don't substitute.
I have two lenses that did not clean up with this were coated; one may actually have very mild fungus damage in the coating or I need something stronger (tbd), and the second lens had distinct pitting in the coating and glass. The pitting had black in it. I assume this was a case of fungal damage beyond recovery.