How to remove decal?

being very careful not to get it to hot I have dun this in the past (10 years ago) using a heat gun, holding it at lest a food away and starting at one side , I heat the area with a sweeping motion until it is about to hot to touch and lay the heat gun down and they seem to peel off using a bondo spreader or even just your fingers pulling evenly and slow, and as it cools stop and reheat the next few inches... Worked for me on an old XLT Ford truck and then I wiped what glue that did not come off with a medium acid tone (mild reducer)