Isopropyl alcohol, also known as rubbing alcohol, works very well for removing label or adhesive residue from plastic surfaces. Soak a paper towel in isopropyl alcohol and wrap it around the residue surface. Let it be like that for 5-10 minutes, and then remove it. The residue will be dissolved and will be stuck with the paper towel. Clean and wipe the surface with a cotton cloth, and your plastic product will be residue-free. Although isopropyl alcohol is good at this job, according to my experience, the four methods mentioned above will work best for ordinary people.