Tony Duell wrote:
Lighter fluid is often a good solvent for removing
adhesive residue...
By far the best stuff I've ever used is "Goo-Gone", a citrus-solvent/
petroleum-solvent blend. Perhaps it (or an equivalent) is sold in the
UK. I've also used Goo-Gone for cleaning ink from plastic surfaces.
It is a bit harsher than isopropanol, but take off some marks that
isopropanol will not, and doesn't visibly affect opaque plastics (or
most transparent ones for that matter).
--Bill