Soak the glass in warm, soapy water
Scrape gently with a razor blade held at a low angle
Apply acetone or nail polish remover to the glue
Let the acetone sit for a few minutes
Wipe the softened glue with a cloth
Repeat as needed until the glue lifts
Use a plastic scraper for delicate glass
Clean the glass with vinegar or glass cleaner afterward
Wear gloves and work in a well-ventilated area
Test acetone on a small area first