Lots of people use nail polish remover and it works...sometimes. Often those stickers leave behind an adhesive residue. I work in the in the retail food industry, which includes my staff applying scale-labels to weighed items. The best removal agent, for those labels that they 'accidentally' stick to the counter-tops, is butane lighter-fluid. This only works for hard surfaces: with a blunt-edged implement (sharp edges will scratch the surface) remove as much of the sticker as possible. Pour a little bit of lighter fluid onto the affected area and rub it around with a paper towel. Wipe again with the dry portion of the towel and, if necessary, finish with soap and water. Removing stickers from paper is a lot harder, and sometimes impossible as the porous material absorbs a little of the adhesive. Try steaming the area to soften the sticker and peel away as much as you can. Leftover adhesive can, sometimes, be removed with a piece of masking tape: apply and remove the tape, several times, to and from the sticky area. Good Luck!