Cover the furniture with waterproof furniture covers when it's not in use, or put the furniture in storage.
Apply a brush-on sealer to the furniture. The furniture will age to silver-gray, but its pores will be blocked so the grains won't rise with age.
Stain the furniture with a penetrating UV-inhibitor stain to keep it looking new. This will preserve the furniture's color and texture.
Clean discolored cedar furniture with a mild detergent solution and a nylon-bristle scrub brush. Next, apply a mild bleach solution and let it sit for a few minutes, but not long enough to dry. Rinse and allow the furniture to air-dry completely.