Armour Products Etch 10 oz Glass Etching Cream

I have a pair of eyeglasses with nice frames that I've been using for years and have been having new lenses put in the frames. The prescription of the most recent set of photo-chromatic lenses was still good but the coating on both the front and back of the lenses had worn down and I could no longer see clearly due to the degradation of the coating. Enter Armour Etch. I applied the creamy like coating to both sides of the lenses with a Q-tip and let it sit for 5 minutes and rinsed and about 90% of the coating was gone. So I did a second application of the lenses doing light rubbing and left on for another 5 minutes and this removed most of the remaining coating. I then did a third application with concentration on the small area of remaing coating while doing light rubbing and left on for another 5 minutes. After this rinse all coating was gone and the plastic lenses were undamaged and were like new. It did not affect the photo-chromatic characteristic of the lenses and I don't miss the coating. I spent $11 on the acid instead of $60 for new lenses. I hope the Armour Etch has a long shelf life because the amount you will use is minimal and I may find another use for it in the future. Highly recommended for PLASTIC eyeglass lens coating removal.