Putting cash in a safe deposit box is legal but may not be a good idea, according to Bankrate. There are no federal or state laws regarding keeping cash in such boxes. However, the cash in safe deposit boxes is not insured by the FDIC.
The lack of FDIC insurance means that if the cash is destroyed in a fire, otherwise damaged or stolen, it can't be replaced, according to Bankrate. Some people store cash in safe deposit boxes to evade paying taxes on it, which is prohibited by the IRS. Jewelry and vital papers are among the most common items kept in safe deposit boxes.