Definitely lighter fluid. I had a similar problem a couple of years ago and posted it to this board. I had MANY replies with various products which I tried with no results -- until I tried the lighter fluid as a last result. Voila! It worked wonders immediately. I then washed the squares I was working on with a mild liquid soap in lukewarm water and let them air dry. Not a speck of residue remained. I wish you luck with getting rid of all your residue!