Bit bothered by this post, as a collector of both silver and some silverplate (the design is the important thing for me), wish I could take all the acid testing kits, sandpaper(!), files, buffing wheels, etc. out of the majority of hands, some of the damage is quite disfiguring (and I'm not all that picky). Most silver can be IDed by the marks if proper research is done, and unless you're planning to scrap it, the intrinsic value of the various silver contents (800 as opposed to 925...) really isn't all that important. My acid testing kit hasn't been touched in at least 15 years, and was really only for use with a touchstone when I was dealing in unmarked antique gold jewelry, and then, frankly, a jeweler friend told me to put it away and let someone who knew what they were doing test for me. If you're talking small pieces, my jeweler has determined metal content for me with his specific gravity scale, coin dealers also usually use this method.