Related Clues:

• Drop in a letterbox
• Letters, collectively
• Drop in a slot
• Stuff in a box on the street
• It's not delivered on Sundays
• Postal sackful
• Attire for Galahad
• It contains a lot of letters?
• Post or body armour
• American post
• Post in America
• Post from Lima
• Modern jargon for letter post, mollusc-slow compared to electronic transport
• American post from Lima
• Do a thousand get sick of being enveloped?