George; One of the several reasons why it is not a taboo in this hobby to clean casino chips is because chips do not have reflective surface lustre like coins, which obtain hairline scratches from abrasive cleaners. Toothbrushes and chips go thogether like strawberries and whipped cream! Chips are meant to be handled and invisible fingerprints do not detract from their appearance or value... which is why there is no tangible benefit from slabbing of chips. They do quite well in 2x2 flips ... or airtite holders for the more expensive ones.