The Postal Service cannot provide special attention to a philatelic cover that has been routinely entered into the mailstream by the sender. Customers are encouraged to supply self–addressed stamped envelopes to protect the items receiving the pictorial postmark from being marred during their return through the mailstream. For customers that do not provide self–addressed stamped envelopes, the postmaster may choose to furnish, at the office's expense, a Priority Mail envelope or box using a G–10 label protective cover for returning the items through the mailstream (see also 9-1.2).