+1 on this. Windex and a plastic scraper. They sell them for removing stickers and stuff. My absolute go to for removing anything sticky is Plexus. Plexus is acrylic cleaner used for aviation windows but has also become popular in motorcycle shops for cleaning visors. We used to use it in the aquarium shop for removing permanent marker from acrylic tanks. Thats how we wrote the prices of fish. It works great on residue. Check your local cycle shop. I should mention it's not cheap but is also great for cleaning your headlights/tailights and will keep them from yellowing.