Depends a bit on what the composition of the adhesive is. Acetone, MEK are worth trying, iso propanol might be worth trying too. I've had success with white spirit & also that very popular spray lubricant **40. As has been said try to leave it on to soften, the paper towel trick works well but some solvents evaporate very quickly, especially in the warm weather, watch out for fumes/ flammability, avoid the vapours & be aware of the H& S issues, some are nasty chemicals......