I am removing a decal that is on a lighted monument/pylon sign which the boss thought would be easy as removing letters off a truck or van. Turns out not to be so. Lettering is very thin like a plastic bag. I heat it up and it gets soft and melts when it cools it just breaks off.

Anyway, I got the lettering off and the glue is left. I was having some success taking the glue off with Goof Off which is some pretty strong stuff but tends to make it all gooie and it evaporates very fast so I have to keep adding more.

I was wondering if somebody knows of something else/better I could use? Denatured alcohol? Paint thinner?

BTW - I tried Goo Gone and I might as well have been using water. It did nothing.

 

If the adhesive is baked on, you might need to get serious and use a paint remover/brush cleaner (different than paint thinner) or a can of vandal mark remover... potent stuff.

 

With dried latex paint, denatured alcohol does the same job as goof off so it might be an option.
Brush cleaner is pretty potent so you might want to test a small area first.

 

I had the same experience removing a political sticker from wifey's rear window. Decal came off, but glue was left. Tried scraping with the flat of a razor blade. NOT. It just gummed up ahead of the blade. I finally used MEK, but even then it streaked a little. A final wash down with vinegar cleared the glass. It was the most difficult to remove I have had.

 

Try using WD-40 or Silicon spray.

 

WD 40 would have been my recommendation as well but Norm beat me to it.