Clear the truck bed of cargo and accessories and remove the tailgate. Vacuum or sweep out all the dirt before washing the surface with water and car soap. Rinse, then drain the holes and ensure that there's no water accumulation on the bed. Use a soft cloth to hasten drying. Use masking or painter's tape to cover all the parts of the truck bed that you don't want to roll on or spray over. Use sandpaper to remove the paint that comes with the truck and any rusting parts so that your spray-in product will adhere well onto the bed's surface. Remove the dust from the bed when you are done. Use gloves, a face mask, and goggles to protect your face and hands during this step. After scuffing and sanding, paint the bare metal surface with an oil-based metal primer or sealer so that the liner will bond to the surface better. Clean the surface with acetone or a manufacturer-recommended substance after the primer has dried. Residual dirt, dust, or oil can cause the liner to separate and peel from the truck bed.