hi Rubin I’ve been faceting since 1965 and still going at it at 76. any metal wheels when done s/b spun dry and store in a zip lock. same with any type cutting and polishing laps. there is splatter and dusting in cutting and can cross contaminate. as far as cutting and polishing laps I’ve just replaced some of my laps. I’ve found on Ebay some china made laps for a fraction of the cost of those made in u s a and since i worked for Crystalite during the 70’s and made the diamond laps back then I’m finding they (china) are not sparing the diamond, the laps are loaded. i bought for cabbing an 8 x 2″ ring grinding wheel of 80 grit for $85 free shipping the same wheel made here is $300+. i bought a set of 3 6″ flat laps for faceting, 120, 600, 1200 grits from china loaded with diamond, metal bonded, for $15 including shipping, that’s total for all 3. myself i generally use only a pure tin lap for polishing everything, with 50.000 grit diamond powder. and run the lap slow and low drip and make kind of mud with the powder. run at very low speed so your not slinging off you diamond mud it polishes quick. the diamond powder is about $15 for 25 carats and last for many stones, again from ebay–china–. do feel free to contact me for any questions. and tricks to faceting. mike zinski (gemmakermz@cs.com)