POLICE have warned elderly residents in the Star area to be on their guard for "door knocking" builders.
They are investigating several reports of pensioners being ripped off after being pressurised into having work done to their homes.
Recently a Fleet resident handed over more than £30,000 to doorstep callers after they had carried out roofing work.
As in other cases, the rogues initially quoted what seemed a reasonable price and then claimed to find other work which needed doing.
Police have received reports of similar scams involving block paving.
Sergeant Dan Alexander, of Aldershot police, said: "This is the time of year when these characters start calling at houses.
"Our advice is simple - people should have nothing whatsoever to do with them."
Reputable builders, he said, did not call out of the blue looking for work.
The best idea is to obtain written quotations from builders who are recommended by relations or friends.
Alternatively builders who advertise in Yellow Pages should be contacted.
"They should be asked to provide names of people who they have done work for in the past," said Sgt Alexander.
"In my experience builders with a good name don't mind supplying this sort of information."