Remove Weekly for Surface Cleaning For best results, apply magnetic car signs to large, flat or reasonably curved areas that are clean, waxed and dry with no air pockets between the magnets and the vehicle. Clean sign and vehicle with mild detergent weekly. Not recommended for repainted surfaces or vehicle hoods. Separating Kiss Cuts– Not recommended Kiss cuts have to be creased before separating. Crease along kiss cuts line and separate carefully along edges.