Officers in Telford say cars that have fold-in wing mirrors can be a give-away to thieves looking for vehicles to steal.
PCSO Susan Tindale, of the police team in Ketley & Oakengates, said: "We often see footage of criminals trying their luck on driveways to see if a car is unlocked.
"One of the tell tale signs of an unlocked car is unfolded wing mirrors.
"If this is a feature on your car, then just make sure your car is locked if your mirrors are down."
PCSO Tindale added: "We patrol in the small hours seeking to prevent this crime and catch those involved. A quick double check from you, and removing valuables, helps reduce the chance of being a victim."