Police say there has been a small increase in thefts from cars in north Lincoln.
These incidents are taking place late at night and have resulted in damage to the vehicles involved.
PCSO Guy McCusker said: “Can I urge all residents to remain vigilant and report any suspicious activity near parked vehicles.
“Car owners can reduce the risk of their vehicle being targetted by taking the following simple measures: remove your sat nav, its mounting bracket and any suction marks on the windscreen, leave the glove compartment open, leave the center console open, do not leave bags, satchels or clothing on the seats.
“These measures will make your vehicle less attractive to a potential thief.
“Please report anything suspicious. The police would rather check out an innocent person than attend later to a crime that has been committed,” he added.
People can contact Lincolnshire Police on 101 or Crimestoppers anonymously on 0800 555 111.