I use a piece of dental floss or string along with a hair dryer. Get the floss / string in the back of the badge while heating the badge area gently with the hair dryer. Run the floss / string up and down while moving along the back of the badge to loosen it. The badge should then easily pull off. Remove the remaining sticky stuff off with some tar and glue remover eg. Autosmart Tardis / Autoglym Intensive Tar Remover. Best if there's two of you as the badge can scratch the paintwork with the movement while being eased off. Easy job really, hope this helps.