Sterno, gel or liquid
IS essentially denatured alcohol, though I think liquid Sterno is slightly deodorized (I may be incorrect.) With either one, gel or liquid, the fumes of Sterno make me want to vomit, so if I am at a function where it is being used, I stay away from the warmers unless I am actually getting something to eat.
My former fondue set's burner took a generous half cup of the stuff.
Lawrence/Maytagbear