Reusable bingo card

A repeatedly reusable Bingo card comprising sheet material having an exposed layer that is microporous and comprises an organic polymer having interconnected microvoids, said exposed layer being permanently imprinted with at least one rectangle divided into individual smaller rectangles, at least five of said smaller rectangles being permanently imprinted with a number of one or two digits, each of said numbers being substantially darker in color than the background are within said smaller rectangles, said exposed layer being bonded to a liquid-impervious support sheet having a Hunter L value on the order of 30-55, substantially darker than the background are within said smaller rectangles but substantially lighter than said numbers, whereby when the area within a smaller rectangle is contacted with a colorless volatile liquid that is a non-solvent for said organic polymer and has a refractive index smaller to that of said polymer, the thus-contacted portions of the microporous layer become temporarily transparent, exposing the support sheet and forming indicia that are darker than said background area but lighter than said numbers, whereby it can be determined that the area within a given small rectangle has been marked but the number therein remains visible, volatilization of said liquid restoring said Bingo card to its original appearance.