Well I do this for a similar trick. I use the stick part of a post it and connect the non stick side of the post it to a strip of permanant double sided tape. then I stick them together. This will make sure the gimmick bill keeps the post it notes and the other bill will be unharmed and ready to go

There is this wonderful glue that I have had great success with besides the 3M spray adhesive. It is called Alenes Tack-It. It goes on wet and dries tacky and does not require a lot at a time. You can also work it to make it as tacky or as least-tacky as you need it to be. I have used it for the Last Dollar by Eugene Burger, having it in a bi-fold wallet for a very long time with no problems. Hope this helps!

Anyone using Dental wax ? works like a charm...

Try a Zig 2 way Glue pen. If you apply it and let it dry before sticking the papers together it should work just like rubber cement. It only stays adhered to the surface it was originally applied to. Really useful for making playing card gaffs.

Cut a small square off a Post-It Note and glue its non-sticky side to the half-bill. The sticky side of the Post-It Note will then be able to stick and then re-stick itself to any banknote you attach it to.

The second solution is obvious but I'll mention it anyway - keep your wallet in another pocket so that you don't sit on it any more.

Not sure how it will work with a bill, but I use Mr. Mole's Sticky Wax (made to secure candles in candle holders).

- Daniel

The wax ring that is installed to seal your toilet to the floor works great...and will provide even the youngest magician with a lifetime supply of was for only a few bucks.