Related Clues:

• Notary's item
• It might threaten the king
• Letter attachment
• Feature of a certain album
• Chisel
• Album item
• Castle in the air?
• Philatelist's concern
• Piece of postage
• Inverted Jenny is a rare one
• PAID, for one
• Characteristic mark
• It's usually stuck in a corner
• Corner chess piece
• Snail-mail need