Stamford police have issued a warning about a holiday scam that asks residents to tip their garbage pick-up crews by envelopes.
They say the envelopes have shown up at a couple of houses in Stamford.
The address is a P.O. box at the Norwalk post office.
Police say Stamford city employees did not leave those envelopes.
They're asking anyone using a private trash collector to check with that company about tips for the crews.