Things You'll Need
Automotive paste wax
After your plastic lawn chairs have been outside long enough, they'll get dirty and often develop a chalky finish caused by the degradation of the plastic in sunlight. You can clean dirt off by washing with detergent -- or even by power washing -- but the chalky finish is likely to remain unless you take the time to scrub it off. This isn't a job for steel wool or scouring powder; both of these can scratch plastic. The abrasive action of baking soda is all you need, and you can restore the shine with wax.
Kill any mold on a plastic lawn chair with a vinegar-water solution. Fill a garden sprayer with a solution of 1/4-cup white vinegar per quart of water and spray the chair liberally. Allow the solution to sit on the chair for 20 minutes; then rinse it off with a garden hose.
Clean excess dirt by rubbing it off with a cloth moistened with full-strength vinegar. Rinse off any areas you treat this way with water.
Dip a sponge in warm water; wring it out and sprinkle baking soda on it. Rub the chair down with the sponge, rinsing out the sponge and sprinkling on more baking soda as needed. Rinse the chair with water when you're done and dry it off with a towel or let it dry in the sun.
Restore shine with automotive paste wax. Wipe the wax on with a rag; let it dry for about 5 minutes; then buff it with a soft cloth.
You can restore shine to your chairs by applying a spray lubricant and wiping it off with a rag.
Avoid using chlorine bleach or cleaners that contain bleach. Bleach degrades plastic and may make the chalky finish even worse. It also causes color fading.
Chris Deziel is a contractor, builder and general fix-it pro who has been active in the construction trades for 40 years. He has degrees in science and humanities and years of teaching experience. An avid craftsman and musician, Deziel began writing on home improvement topics in 2010. He worked as an expert consultant with eHow Now and Pro Referral -- a Home Depot site. A DIYer by nature, Deziel regularly shares tips and tricks for a better home and garden at Hunker.com.