Things You'll Need
Glass and window cleaner
Rubber can be used as an extremely strong adhesive. One of the more popular rubber adhesives is known as rubber cement. It typically comes with a brush applicator and can be used for several different things around the home, office and school. It is great for using with craft projects and repairs. When it gets stuck to hard surfaces like glass, no ordinary cleaner will do the job to get it off. More drastic measures must be taken to remove this strong adhesive.
Scrape off as much rubber as you can with the razor blade. The razor blade can get under the rubber and make direct contact with the glass, enabling you to pick up the rubber and remove it quickly.
Spray the glass with the cleaner.
Wipe as usual with a paper towel. Scrub if necessary.
Repeat until all residue is gone.
If a razor blade doesn't get all the rubber off, you can use lighter fluid to remove the excess. Then clean with the glass cleaner as usual.
Exercise caution when using a razor blade to avoid nicks and cuts.