A Dead Drop uses a Dead Letter
Box (or DLB), a physical location where material is covertly
placed for another person to collect without direct contact
between the parties.
Good locations for dead letter boxes are
niches in walls, in and around public trash receptacles,
in and around trees and shrubs, inside vegetables such
as pumpkins, in someone else's mail box, between books
in a public library, inside a paper towel dispenser, etc.
The key to success is ingenuity, so none of those mentioned
are good ideas.
Drop site under this footbridge over Wolftrap Creek at Foxstone
Park (Hanssen Case, February 2001)