Related Clues:
- Letter enc.
- MS. accompanier
- Return mailer (Abbr.)
- Enclosure inside an enclosure, for short
- Encl. to facilitate a response
- Postage-paid enclosure: Abbr.
- Cover letter letters
- Manuscript enclosure: Abbr.
- Epistolary courtesy
- It may hold a rejection slip, briefly
- Letter enc., maybe
- Enc. for response
- Letter insert, briefly
- Letters on a can of motor oil
- Motor oil letters