I tried the finger nail trick but as I chew the hell out of mine I had to use the wife's---worked fine and that was nine years ago and they have not came back the decals not my nails
I used my nails and then used the back of the sticker to pull off the glue. Afterwards, I used olive oil to remove the rest of the goo. Works on my new helmet too. Afterwards, use soap and warm water to remove the residual oil, then wax that baby.