Quote:
1.3 The following are Invalid for use
d. U.S. stamps that are mutilated or defaced; cut from stamped envelopes, aerogrammes, or stamped cards; covered or coated in such a manner that canceling or defacing marks cannot be printed onto the stamps; or overprinted with an unauthorized design, message, or other marking.
Roll the dice if a postal employee will consider them damaged, mutilated or defaced.
Don