Mix equal parts of distilled white vinegar and hot water in a 3-gallon pump sprayer. Cover the floor beneath the ceiling with tarps or old sheets -- this may get messy.
Slip on a pair of old clothes and a pair of goggles to protect your eyes. Climb your ladder. Saturate the glue with the vinegar and hot water mixture.
Give the vinegar and hot water at least 30 minutes to work its magic. It is normal for the mixture to drip from the ceiling, so do not be alarmed -- that is what the tarps are for.
Use a plastic paint scraper to scrape the glue from the ceiling.
Wipe the ceiling clean with clear water and a soft cloth after scraping. Buff the ceiling dry with a soft towel.