Peel off as much residue as possible with your fingers or a plastic scraper
Rub the area with warm soapy water
Apply rubbing alcohol to a cloth and wipe the residue
Use white vinegar on a cloth and rub the sticky area
Dab a small amount of cooking oil or baby oil, then wipe clean
Use baking soda mixed with a little water to form a paste, then rub gently
Try acetone-free nail polish remover on a hidden spot first
Use a commercial adhesive remover made for plastic
Wash the plastic with soap and water after removing the residue
Dry the plastic completely before using it again