Agreed on the over-analyzing comment. OP -- there's no reason to wrap it in foil. The entire point is to draw as little attention to the package as possible. Doing a bunch of extra stuff isn't necessary - just make sure you package it well and professionally, track it, require signature, etc. You also don't want to put tape directly onto the cash as it can cause damage. Also, there's no question about this: NEVER USE A RANDOM RETURN ADDRESS for cash-in-the-mail packages. Sending cash is not illegal, so there is no reason to risk it getting lost if for some reason it has to be returned to you!