The heat gun is the best thing I have found. If you do it slowly and work the decal back on it's self you will get most of the adhesive with it. The ones I have done have been on the plane for a while. A lot of the sticky stayed on the covering. I used Trim Solvent to get the sticky off. I just dabbed some on and rubbed it around with my finger tips. It turned the adhesive into a jelly. Then I just wiped it off. It did stink up the place but did not take much time.

David