Leaflets offering tree and gardening services are being handed out.
Devon, Somerset and Torbay Trading Standards Service is warning people in Exeter about leaflets that may have come through the letter box.
They offer tree and garden work. But Trading Standards say you should never agree to work offered by unsolicited doorstep callers.
Their advice is to get three quotes from reputable businesses. They also say you can get recommendations from friends or via Buy With Confidence
In the alert the add: "If you are concerned someone is at risk, always call the police. If you are concerned rogue traders are operating in your area, always report it. If someone knocks on your door and you are not sure, don’t open the door."