I've had several people tell me that this stuff works wonders, if you have light colored plates that have gray or silver marks from silverware or if your porcelain toilet has gray scratch marks from the metal on the toilet scrubber, same for porcelain sinks. I've also heard it does wonders for pots that have been scorched on the bottom and light colored grout. I haven't used it yet but I've heard nothing but good things and I found this coupon so I thought I would share. Anybody use this??