Related Clues:

• Post office sackful
• Letter's attachment (Abbr.)
• Weekday delivery
• It may be junk
• SASE, for one
• It often contains lots of letters
• It might be four letters
• "You've got __"
• Check sent with a ltr., e.g.
• Vacationer's accumulation
• Env. thickener
• Drop in a letter box
• Postal deliveries
• Return envelope, e.g.: Abbr.
• Letters and such