Related Clues:
- Rubber-__ (approve unquestioningly)
- Passport Control device
- Corner square?
- Part of a philatelist's collection
- One might be forever
- Sticker on an envelope
- It may say 'Forever'
- 'Forever' postal purchase
- Benjamin Franklin is depicted on the first U.S. one
- Impress, not intangibly
- It may take a licking
- What takes a licking and keeps on sticking?
- Inked indication of approval
- 77-Down is on the most collected one in U.S. history
- Put your foot down, Frank