The public are being asked to be vigilant to anyone stealing or damaging TT items from the course.
Police say they've had reports of damage being caused to the crash fencing and of items being stolen.
They say the safety fencing is crucial to keeping the racing safe and any damage can compromise how effective it is.
People have also been warned against taking signage such as the prohibited area signs - police say although they can seem like good souvenirs the consequences of removing them could be catastrophic.
Anyone who sees items being taken or damaged is asked to contact Police Headquarters or Crimestoppers.
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