You can get stainless BB's in varied sizes. here is a site that has different options. I have never ordered from them, but have used copper bb's before with good results
Terrazo and Mrble supply has or used to have a truely silver coated mirror that has a "nugget" shape as opposed to flat shards. It looks like little chunks that have been hacked from a larger block with a blunt axe. Appealing stuff. I don't know if this is what Shawn is distributing now.
You can also get zinc and brass shavings - clean - from Congilossi (sp.?) Or zinc or brass cubes in 1/4" or 3/8" also clean.