Use heavy-duty, harsh commercial “clean-up” solutions on mirrors. Most of them contain abrasives, alkali, or acids or all three. Remember, the three “A’s” (abrasives, alkali and acids) are all harmful to mirrors
Use dirty or gritty rags, knives, scrapers, emery cloth or other abrasive materials for cleaning
Abuse the critical edges—most mirror failures are at the edges where “spillover” solutions attack the backing at its most vulnerable point
DO:
Use any of these three types of recommended mirror cleaning solutions:
Weak (5–10%) methyl, ethyl, or rubbing alcohol water solutions, such as Windex, Solox and other household glass cleaners are examples
Weak household ammonia water solutions (provided they DO NOT contain any alkali… many do)
Weak (5%) household vinegar solutions (provided odor is not an issue)
Use a clean, soft rag or paper towel when cleaning mirrors
Protect the edges from “spillover“ by applying cleaner to the cloth, rather then directly on the mirror. Also, it’s a good final cleanup practice to wipe the edges clean and dry off any “spillover.”