Peel off as much adhesive as possible with your fingers or a plastic scraper
Apply warm soapy water and let it sit for a few minutes
Rub with a soft cloth or sponge
Use rubbing alcohol on a cloth and gently wipe the residue
Apply a small amount of white vinegar and let it soften the adhesive
Use cooking oil, baby oil, or peanut oil to loosen the sticky residue
Wipe away the softened adhesive with a clean cloth
Wash the plastic with soap and water after removing the residue
Dry the plastic thoroughly
Test any cleaner on a small hidden area first
Avoid harsh solvents like acetone unless the plastic is known to be safe for them