In some cases, your car might have a temporary tag, which might be made of paper, and highly susceptible to water. Temporary tags are issued by the DMV when district residents have their vehicles inspected before the vehicle can be fully registered.  These are required by law to be attached to the car until your actual license plates arrive. It is advised that you don’t take the temporary car tags into the car wash with you since they will be ruined and end up as debris on the car wash floor. However, a good solution to this is to use DIY car washes, where you can pay to clean your car yourself.  Since you’ll be washing your car yourself, no one would mind if you placed your temporary tag into the car and proceeded to wash the car to your heart's content!