Officers who find unsecured doors and windows will push them open, blow up a balloon and send it inside.
Police are breaking into peopleâ€™s homes and leaving inflated balloons behind in a bid to make people lock their doors.
South Cambridgeshire police has launched the campaign to make people aware of the need to lock their homes properly. They are also targeting sheds and putting postcards in unlocked cars and have already found 70 cars that were not locked properly, including one full of Christmas presents.
Each balloon has an advice sheet attached as well as a â€˜security surveyâ€™ completed by officers.
Inspector James Sutherland said: â€œThis is not about traditional crime prevention â€“ we are trying to make communities safer and raise awareness about the risks.
â€œAs part of the operation officers will be concentrating resources on one village per day, every day for 30 days.
â€œAs well as the shed stickers, balloons and postcards, weâ€™ll also be selling shed alarms and completing security surveyâ€™s to send a strong, clear message to burglars â€˜get stuffedâ€™.â€
Police are not allowed to enter private property without a warrant.
There have been 139 thefts from vehicles, 119 reports of shed burglaries and 160 burglaries in South Cambridgeshire since September.
Police leave balloons in unlocked homes in bid to make people lock their doors