This is a pair of solid cork dice. The cork is unfinished and is naturally anti-microbial. It can be cleaned with water or any ecologically friendly cleaner. If there are any marks (ink, sharpie, wine), they can either be wiped off if still wet or easily sanded off. We are a furniture designer that uses a lot of cork (it's renewable) and these designs are made from the pieces that are leftover. The cork we buy comes from Portugal, it is made from the bark of the cork tree that is ground up after the wine corks and stoppers have been punched out. Therefore it is post-production, pre-consumer waste that is compressed into slabs and cylinders that are used in a variety of industries.