RTS is a term use in envelope when the received want to inform the sender that the letter is not belong to the address or the person already moved. The full term is Return to Sender.
Sometime certain peoples will do a remark or 2 just to remind the sender please stop sending. This mean occasionally we got some very interesting message to read on the return envelope.
I came across one of the very cute RTS this week. Please allow me to share it here
I am totally understand how pissed off the person was. A person you consider GONE and HISTORY but still the stupid firms again and again sending notice for him to your box.