Police officers in the Skye, Lochalsh and Applecross area are urging members of the public to be on their guard of suspicious callers.
In particular officers would ask people to be aware if they are offered services such as tarring and property maintenance.
Acting Inspector Bruce Crawford said: "It is well known that such door to door cold calling can be a front for criminal activity and I am particularly concerned that vulnerable members of our community may fall victim to unscrupulous criminals who prey on such vulnerability.
"Anyone offering such services should be asked to produce a written quotation bearing the full name and address of the company and information relating to cancellation periods available. No money should change hands prior to work being commenced.
"In a rural community we rely on friends, family and neighbours to look out for those most vulnerable to such fraudulent activity.
"Those intent on targeting the more vulnerable in our communities show no concern for the emotional or financial well-being of those they offend against and are very difficult to track down if the standard of work proves to be unsatisfactory.
"My advice is to use a reputable company, do not agree to any work being carried out before you have spoken to someone you trust and never hand over any money or bank details until you are completely satisfied."
Anyone with information regarding doorstep crime should contact 101 or Crimestoppers if they wish to remain anonymous on 0800555111 and their information is not urgent.
How can I protect myself from doorstep crime?
• Be on guard if someone turns up unexpectedly.
• Keep front and back doors locked.
• Use the door viewer or nearby window when answering the door.
• Fit a door chain or bar – use it and keep it on when talking to callers at the door.
• If you’re not sure, don’t answer the door.
• Don’t feel embarrassed - genuine callers expect you to be careful.
• Only let callers in if they have an appointment and you have confirmed they are genuine.
• Always ask for identification badges of anyone you answer the door to, but don’t rely on them. Identity cards can be faked – phone the company to verify their identity.