I have been thinking about doing some customwork to my M&P I have seen different finishes and have tried to look into what methods are used to achieve these. Recentley I have been remodeling part of a local precious metals refinery and I have been offered to have them blast my slide for free to achieve a two-tone look, but what media do gunsmiths use for this and does any part(not removable) have to be masked off prior? Still not sure what finish I will go with but I like knowing how to achieve my options. Thanks for any help, Anthony