Originally Posted by LarThaL
I used "Goo Gone" automotive formula with some cotton gauze and a small hard plastic spatula. Takes a bit of work depending on how much residue is left after you remove the lip. I used a plastic trim tool to "chisel" the lip off after applying painters tape to the surrounding parts of the car.
This method did leave some very faint scratches in the clear coat but I didn't care since I was installing the new piece. It wasn't anything that couldn't be easily buffed out with some rubbing compound and an orbital polisher, however.
Easier if you let the Goo Gone really soak into the foam tape residue.
It's even easier to remove the spoiler with dental floss or fishing cord.