I agree the U.S. note (Red Seal) and the star note might be worth a bit more than face. The $10 note, I doubt more than face value as from time to time you still run across them in change.
The condition here is the issue and the above mentioned 2 notes that have value, lose a good portion of that being they are not in mint condition.

Perhaps later on Mike Poole our resident currency expert will chime in

In the few instances I have had to send notes, I have generally placed them in a plain white envelope and then between two pieces of cardboard and mailed them in a small manila envelope