Archemist":3r1kqlk0 said:most stickers of a certain age will be solvent based adhesive - white spirit, a dab of unleaded, possibly (though unlikely) meths, may well soften the glue and remove the remaining adhesive. You could also try a paint thinners or solvents (cellulose thinners, humbrol, etc).
Though I'd say these are very unlikely to damage proper anno - as suggested above try on an inconspicuous area 1st - the wife's bike for example
GL