Yep, the people who remove lettering for a living (the outsourced vendors or the people in the shop at a carrier) use a heat gun, then the corner of a plastic scraper (or a fingernail) to lift the edge of the decal and peel back while heating the rest. One the decals are removed, a little Goo Gone or other adhesive remover rubbed onto the residual glue with a rag will take care of it.
This is how we took our FedEx Signs off the old truck and it worked pretty well. We removed the signs when it was very cold (snowing) and without the heat gun we would probably still be working on the lettering. We used the Goo Gone as well and our truck looked really good when we sold it. It was really hard work though and it took the two of us a day to get all of the signs off. Once we got the hang of it the signs came off rather fast and we would take the signs off ourselves again using this method.
When you watch someone who does it all the time do it, you see how easy it can be. Doing it yourself, it takes nearly an entire truck for it to get easy. But once you've done it, you're good to go.This is how we took our FedEx Signs off the old truck and it worked pretty well. We removed the signs when it was very cold (snowing) and without the heat gun we would probably still be working on the lettering. We used the Goo Gone as well and our truck looked really good when we sold it. It was really hard work though and it took the two of us a day to get all of the signs off. Once we got the hang of it the signs came off rather fast and we would take the signs off ourselves again using this method.