First, determine if you’ve got a layer of window tint on your vehicle windshield or otherwise.
It tends to be a little easier if there isn’t a tint applied as the adhesive residue from the road tax would be easier to remove.
Otherwise, extra care is recommended when removing expired road tax stickers from tint.
Assuming you do have a layer of window tint applied on your windshield, use the following steps:
1. You’ll need cotton-towels/microfibres, a solvent, for example alcohol-swabs (from the pharmacy) or lighter fluid (i.e Zippo) and a detergent. A basic pen-knife and a spare plastic card would suffice as tools.
2. Place soft cotton towels or microfibres on the dashboard area below the windshield.
3. Paste a few layers of quality cellophane tape on the back of the road-tax sticker overlapping the each layer by about one centimetre so that the entire sticker is held together in one piece. It’s a simple trick but will make your job removing the road tax sticker so much easier.
4. Using the pen-knife, carefully pry open a small gap under the edge of the road-tax. Leveraging carefully, begin to peel away the sticker slowly.
Spread even pressure widthwise so that you can retain as much of the road tax in one-piece to make for easier cleaning later on.
5. Once the sticker is removed, wipe the alcohol swab or using an older disposable towel, apply some of the lighter fluid onto the leftover adhesive residue. Gently rub in a circular motion and the residue should come off easily.
6. Next use a piece of newsprint and wipe away any of the solvents left over during the removal process. Immediately spray some detergent onto a cotton towel/microfibre and clean the affected area. Wipe with a clean damp microfibre. That should remove any streaks and unsightly marks.
7. When you apply the new road tax, try using a clear thick film for the adhesive portion to stick onto first. This would make it easier to replace the next round. They are usually provided by service centres, tint-installers or detailing facilities.
If you can’t find one, try buying them from hypermarkets and stationary or accessory shops.
Things to avoid
1. Don’t use a hair dryer to heat up the expired road tax sticker as the windshield might crack if there is excessive heat in a localised spot. Tint installers use heat guns/hair dryers but understand how to control their usage better.
2. Heavier duty solvents should be avoided as they might deform or cause the tint film to degrade.
3. Avoid using polishes/compounds to remove residue on tint as they might abrade the material. They are suitable for windshield’s that aren’t tinted as you’ll be working directly onto glass.
adapted from http://star-motoring.com/Features/Finishing-Touches/Removing-road-tax-stickers.aspx