What's the best product to remove the adhesive from a window decal on 1994 GMC Safari

I'm having a difficult time removing the sticky residue from a window decal.

Asked by for the 1994 GMC Safari
Lighter fluid will take it off. Put some on a rag not a paper towel it works great.
Just dont strike any matches while doing this.
1 more answer
You could also use brake cleaner or multipurpose cleaner.