I bought it to try it out. I brought home half a dozen of my slabbed coins that had scratches on them obscuring the coin. I rubbed 20 sec with #2, finished with #1 and the slabs are like new. I spent $10 + shipping and insurance to reholder a bunged up NGC proof seated half last year and now I wish I never had. This works like magic on NGC and PCGS slabs and I've tried it on both today. The coarsest cleaner, #3, is one I only tried on a seriously scratched PCGS proof
Liberty nickel. I highly recommend this product.