Slate- 400 grit sandpaper or maroon scotch brite.
Glass/crystal- 120 grit emory cloth and occasionally a stone.
Copper- 400 grit sandpaper or green scotch brite
bead blasted aluminum- an alcohol pad is what I hear works best.
Slick aluminum- anything from 400 grit sandpaper to 240 grit.
Ceramic- usually green scotch brite, but some have better luck with some more course sandpaper and some guys like a stone. I don't think the scotch brite does much to the surface.
Titanium- green scotch brite.
Some strikers and calls need a more conditioned surface to run well. Some glass calls sound completely different if you leave the dust on the surface after you condition it as opposed to wiping it off.
