From Magic by Gosh
The magician removes the four aces from the pack, displays them in a spread and places them on top of the deck. He explains that the pips on playing cards are actually a solid model which has been greatly compressed. After the understandably skeptical reaction from the audience, the performer offers to prove his claim. One of the aces is rubbed on the magician's left palm and when it's lifted away, a sponge spade has appeared and when the card is turned the spade pip on the card is gone! One by one, the effect is repeated with each of the three remaining aces in a variety of ways-the pips may be plucked from the card, scratched or slapped off as the magician chooses.
Using the four sponge pips, the magician then performs any of his favorite sponge routines, making them jump from hand to hand, even into a spectator's closed fist!
All four of the sponge pips are then placed into the magician's hand, he places his closed hand over the deck and opens his hand, quickly bringing out down onto the top of the deck. When he lifts his hand, it's seen to be empty-the sponges have disappeared! Upon turning over the top card of the deck, the Joker is seen-with the four missing pips strewn across the face!
After giving the audience sufficient time to recover, the performer removes the four deuces from the deck and spreads them showing the faces. The four cards are slapped against the palm of the magician's hand and when they're pulled away, he's holding all four sponge pips and the 2's are shown to be missing their bottom pips!
Again, any of the performer's favorite sponge routines may be performed using these sponge pips. To conclude, the magician places the heart sponge pip into his left hand, then the club, diamond and spade into his pocket. He asks the audience what is left in his hand and no matter what the response, the performer opens his hand to reveal a four-inch sponge heart!