When applying a window decal to a car, make sure the window is clean before lowering the decal in place and sealing it to the window by rubbing it into place. After about 24 hours, remove the protective film on the front of the decal to complete the application.
Pick a day with moderate temperatures for best results during application. Extremely cold or hot days can cause expansion or shrinkage in the decal, leading to a less secure placement on the window. Use rubbing alcohol or a mixture of soap and water to clean the window before applying the decal, and use a lint-free cloth to prevent leaving behind small pieces of debris that can interfere with the decal's placement. Rinse away any soap residue if using it as a cleaning agent. Allow the surface to dry completely before applying the decal.
Prepare the decal for application by rubbing the front of the decal with the edge of a credit card. This removes any bubbles present on the rear of the decal on the transfer tape. Remove the backing paper protecting the tape side and then place the decal onto the dry, clean window. Set it in place by rubbing the decal surface with the credit card, then allow 24 hours for the adhesive on the decal to set.
Search the decal for any high spots caused by air bubbles. Pop the bubble with the point of a needle, then rub the decal flat again. Peel off the protective film over the decal.