It is a very common advice given by the credit card consultants that you should not close your idle credit card accounts as they will help you build a better credit history. However, idle credit card accounts can be double edged swords. A credit card identity thief can easily use your idle accounts to do illegal activities.
Identity thieves can change the address on your idle credit card accounts to procure a new credit card in the new address sighting the reason that you have lost the original card whose address they changed. They can also open new accounts in your name to do virtually anything they want. The longer these thieves remain unspotted, the more damage your financial condition will have to bear.