As one who's sprayed literally acres of lacquer finishes, some on musical instruments, but mainly on furniture, I'll advise the cigarette-lighter fluid route. Lighter fluid is naphtha, also known as camp-stove fuel. It is safe on lacquer finishes such as guitars. DO NOT USE ACETONE or nail polish remover or any such other stuff, even quickly or you'll etch the finish (or perhaps worse) Oils won't do much to soften the residue of soft adhesives like scotch tape. At best they'll emulsify enough so that vigorous rubbing will remove the stuff by abrasion. Not recommended.