I have my share of pewter and brass drinking and dinnerware (Plates, mugs, etc.) and wonder how reliable these kits are. (Brass is SUPPOSED to be an alloy of copper and zinc, but I have heard that lead can be added to the mix) I have certainly read the on-line reviews, but have no idea how accurate those are. Call me cantankerous, but I would not be surprised if such review blogs were flooded with paid employees posing as legitimate customers raving about the product. I work in tourism and people put up fake reviews all the time. It's called Tripadvisor. (Ohhh, don't get me started on that!)
I used the 3M product and I am gratified by the negative results I got for the item I tested, but I want to know how legitimate that test really is. I don't know which product reviews to believe.