We have some tumbled travertine (4x4, loose, not laid yet) that is sealed
with TileLab SurfaceGard Penetrating Sealer (the good stuff). We want to
remove that sealer and then apply a color enhancing sealer.
I tried Superior Pro-Strip Sealer and Adhesive Remover. It just beaded up,
even after an hour.
In a small test area I wiped it with a little no-rinse liquid paint stripper
(pure solvents, no residue) and it seems like it would do the trick. But I
really don't know about applying something like that to a marble.