I learned from the window tinting guys. Spray a soap/water mix out of a $0.99 spray bottle, then apply the BG sheet and use a "bondo spreader" or a credit card to work out the air pockets/bubbles. Once the bubbles are out the BG material sticks/dries and you have a smooth install that can be pulled off later. Tape is the easy way out and you can tell when someone uses tape..

