We use laquer thinner

 

Soaked it with WD 40. New box of plastic razor blades. Spent the afternoon getting all off. Next step is the side boards. I will use my steam/hot water power washer for them.

 

Don't listen to some of these people. Do NOT start blasting it with high-pressure water (stick your hand in front of that and tell me you think that's okay for your paint). GO TO A DETAILER they will polish it off with rubbing compound and not damage your paint.

 

If your truck was waxed well then it shouldn't stick and should be easier to remove.