Lincolnshire Police are warning people to be vigilant after recently receiving an increased number of reports about uninvited traders turning up on doorsteps across Lincolnshire.
It comes after a resident was charged £200 for tea towels and other miscellaneous items.
A police spokesperson said: “If you are not sure, do not open your door.”
If you notice any suspicious person or vehicle, contact Lincolnshire Police immediately. Call 101 or 999 in an emergency.