Magnets are not always shipped flat, so it is highly recommended to lay them flat on the hood or roof of your car in the sun for a couple of hours before use. This will help evaporate any moisture build-up that accrued during shipment, if any, and it will help your magnets maintain a flat profile. You may want to keep them in a flat box or on a flat surface at all times and only handle them when cleaning and installing, to help maintain their flatness. We recommend you keep your magnets clean on both sides, as well as the placement area on your car door or area of your choosing must also be clean and free of oils, dust, dirt, and other build-up. It's a good idea to take your magnets inside your home or garage away from the elements and lay them flat in a cool dry place, while not in use. You can clean your magnets with a soft moist cotton cloth with water, no abrasive cleaners. It's recommended that you do not stand them up on their side, as they may wilt and might not lay completely flat on the surface of your car door after wilting. These suggestions are to help the longevity of your magnets.