Soak the area with warm, soapy water
Let it sit for 5 to 10 minutes
Scrape gently with a plastic scraper or old credit card
Apply rubbing alcohol or white vinegar to a cloth
Rub the residue until it loosens
Use a small amount of cooking oil or peanut butter on stubborn residue
Wipe away the residue with a clean cloth
Clean the glass with glass cleaner
Dry with a lint-free cloth
Repeat as needed for remaining residue