You can use lighter fluid or in Australia you can buy a product called Un-Du from Bunnings which can be found in the paint section.
Wet the area making sure you can see the fluid seep under the tape or snipe. With a small knife gently lift a corner of the tape. Take it slowly.
The fluid will evaporate fairly quickly and won't leave a stain. You can apply more liquid if need be.
The older the tape may leave some residue after the tape is removed but you can apply more fluid and rub it off with your finger.
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