Ok the effect is more or less as described and looks great. Michael is a genius with gaffs! The
effect is not squeaky clean however. You should know that you do have to ditch something at the end.
That's the bad news. The good news is that the way the effect is structured there is a lot of
misdirection at the end as they both examine their borrowed bill and find their card back in the
deck (or some other location). This should give you ample opportunity to do the final bit of
clean-up. I like it.
Michael doesn't mention it but a nice touch is to force a duplicate
of the gaff card in an earlier trick so they have experience handling the card. It's a simple matter
to ring in the gaff after that.