Mineral oil or baby oil (mineral oil with scent). Real casino chips such as these made by Paulson are made to ingest oil from players hands. Over time the colors pop out to a vibrant level. When you buy a very dirty retired casino set you usually have to clean thoroughly with dish soap and toothbrush on a per chip basis (pain in the neck). With this some of the luster is lost with oil removal when cleaning. So, lots of people will re-oil to get them popping again.

What do you “Oil’” them with ?? and why, whats the benefit??