I’m still reading the fantastic book Be More Funny by Christopher Barnes. One of the things he writes about is using an odd prop on place of a normal one. His example uses sliced cheese in place of cards for a card trick. His routine is great and really well thought out.
It got me thinking of a trick that could be done with something unusual. How about using a cracker in place of the coin for coin in ball of yarn? They’d sign the cracker. Then you do the old gag where you do a false transfer and reach into your pocket for magic dust to sprinkle over your hand. The dust is the smashed cracker. This is played for laughs. Then later the signed cracker reappears in the ball of yarn, or impossible location.
I like the idea of this trick because the cracker is destroyed in a gag and people will forget about it. When it reappears, hopefully it will actually be a surprise.
Another idea would be to openly smach and restore it, then eat it before the signature verification as a gag.