Aloha We used GlassPlus and surgical gauze to clean the mirror of a 16" RCOS that was covered in mold. The scope was in an observatory covered in a black trash bag in a part of Maui w/ high humidity and cool. The mirror was put in a laundry sink w/ warm water running on it for 15 minutes, then sprayed w/ GlassPlus, allowed to sit for a bit then GlassPlus soaked gauze was dragged (no pressure) across the mirror and disposed of after a single use. We'd do 10 drags w/GlassPlus sprays in between. We'd rinse in ionized water, check and do it again. Our final rinse was w/ ionized water as alcohol needs to be near 100% pure or it leaves impurity rings. Excess water was blown off w/ canned air and small drops were picked up w/ lens tissue and surgical gauze. Windex and tissues work too. Aloha Rob