Everyone has said almost everything on the reviews. My personal option for the supposed swapping to
the gaff $5, then deal with the $10 bill afterward.
I use a Hip Pocket wallet that has a
center divider in the paper money (People use that to keep small bills left, Large bills right
etc..I use a Badger Wallet has one).
I setup my wallet with the working bills ($5 / $10) on
front, then under the center divider another plain matching $10.
(Quick nod to Joshua Jay's
"Transporter" I also have my "Magicians ID Card" there too - which utilizes the divided wallet idea
too..*wink wink*)
Follow the provided routine and then after the $5 changes to the $10, open the
top showing the $5 back in wallet and as you remove the $5 leave the gaff $10 and slide out the
regular $10 under the divider.
When everyone had a look, put the $10 behind the divider, and the
$5 in front with the gaff $10. and you're RESET! You don't make a "move" out of it, just keep
dialoguing with them and you are just taking money out and putting it away.