The serial number secret is known. I have seen it in a few books for amateurs. The label idea also isn't new. However, magicians force color labels or numbers to mark the bill. The produce label already exists. Using it is faster and looks more impromptu since you are not removing extra stuff. I would like a signed bill version where I never touch the lemon using no loads. Besides using a stooge or a lot of gimmicks and setup, this is 1 of the best no thumb tip versions. It could be an easy reputation builder. Highly recommended.