Wd-40

I have always found WD-40 to be useful for only one thing: loosening money from my wallet. It is useless as a lubricant, useless as a penetrant, useless as an ignition water displacer, and while it -- like any other light mineral oil preparation -- is effective at removing gummy adhesive residue (such as where tape or labels have been peeled off), there are much more effective preparations for that task.