do a test and use lighterfluid, the liquid you pour into a zippo ?
Its a petrol cleaner, so evaporates nicely, but would also soften the sticky glue on the back of the sticker.
Just be careful first !
Thanks CC.
So you tell me to kinda "polish" the surface of the sticker with this fluid, which will pass through the sticker and will "disintegrate" the glue or trying to remove the sticker a little bit and spraying some fluid under it ?
Your mileage will vary and it might leave some residue but a hair dryer or heat gun can be used... If using a heat gun make sure you don't go overboard because it can and will burn the cardboard or discolor any ink...
I vote for hair dryer... I did this once from a cardboard box, I heated the sticker and used an exacto knife to slowly peel the sticker off... Good Luck