I've come into possession of a Kabar whose leather sheath at one time has some turns of duct tape wrapped around it. The tape is gone now but of course the tape residue remains. I was about to wipe it down with Goo Gone but noticed that the label indicated that it was not for use on leather. Well hell. I imagine that this is not a common problem but was wondering if perchance any of you had had occasion to get tape residue/tar/gum/etc off of leather and what you found to be effective. I'd like to be able to look at that old leather without the white ghost of duct tape past getting in the way.