What's daub? Well, daub is a tiny smear of any greasy substance that will create a distinct mark on a card. Once the card is marked in a deck, many tricks are possible. Gamblers often use daub with a tiny trace of gilt paint worked into it, so the smear catches the light and signals the marked card. Gusias had wide army camp experience with gambling and when he returned from overseas, he and Marlo worked out these effects. Any tiny smear of grease will give you sufficient results to try out the tricks. Marlo and Gusias have some interesting problems and even more interesting solutions here.