What's the best way of removing sticky plastic labels from painted walls before repainting ?

I always use a glass scraper then sand the area, Paul

Hi I have only ever used a window scraper with a very sharp blade. If you use this, be careful not to damage the wall with the blade though.

I would suggest using a window scraper i.e. a stanley blade very gently to remove the bulk of the sticker and then use methylated spirits to clean off the backing glue. Allow the meths to break the glue down for a few seconds before wiping off. Meths evaporates quickly so don't use sparingly! Good Luck