Move the resin furniture to an area, such as the lawn, where you can easily clean it without worrying about making a mess on your patio or deck.
Pour some baking soda into a medium-sized bowl and fill your bucket with warm water. Also add warm water and bleach to your spray bottle. Use a 50/50 mixture of water and bleach.
Spray a small, unseen area of the resin lawn furniture with the bleach and water solution and gently rub it in. Check the furniture to see if it has been faded or discolored by the bleach. If the furniture is negatively affected by the bleach, discontinue using it and proceed to Step 4. If the resin is unaffected, spray the entire surface of the furniture with the solution and wait 15 minutes.
Dip a sponge or soft-bristle nylon brush into the bucket of warm water and then dab it into the bowl of baking soda. This should create a baking soda paste on the brush or sponge. Rub this paste onto the furniture using a circular motion. The baking soda will act as a mild abrasive, helping to remove built-up grime and polish the resin.
Continue scrubbing all of the lawn furniture in this manner until you're satisfied that the furniture is entirely clean. After the lawn furniture has been washed, rinse the surface with a garden hose. Allow the furniture to air-dry.