Removal is surprisingly easy really with a common substance that most households have somewhere - silicon spray (WD40 or similar). Simply soak the paper part of the label with the liquid and leave for a short while - then just peal off. Once pealed off there is a gungy mess that can easily be cleaned off (polished) with absorbent paper (kitchen towel etc.)
Points to note:
1. To avoid overspray I prefer to spray a little in the cap and then use an old small paint brush/end of a pencil/absorbent paper/etc., to paint it on.
2. On delicate and/or absorbent surfaces (e.g. wood or matt paint) the silicon spray can leave a mark. If this is an issue don't use silicon spray.
3. Instead there are a number of special water based solvents available that will cause less of a problem such as RS components LRM (Label Remover), but these can affect some types of plastic - you must test them on an inconspicuous place first.
4. On plastic labels the solvent (both silicon spray or LRM equivalent) can only attack the edge of the label (cannot soak through the plastic).
- If you carefully score across the plastic you will give more places for solvent to get at the adhesive but it is still not easy.
- Score the plastic so that you pull the label off in strips.
- If the solvent cannot get through to the adhesive the narrow strips still makes it easier to get the label off anyway.
- Use of a silicon spray will actually make it more difficult because the water will not soak through the paper when you come to do it properly.
- If in doubt try water first, then if the adhesive is not water based you can leave it to dry out and then use silicon spray.