Wipe your wicker furniture down with a clean, dry cloth to remove any wet or dry stain substances. Use a stiff-bristled scrub brush to remove stains from in between the woven wicker.
Vacuum the surface of your wicker furniture using a brush attachment. Your vacuum will extract dust and stains loosened by the cleaning cloth and scrub brush. Vacuum the underside of wicker furniture as well, since stains can easily saturate through the open weave from the top to the bottom.
Wear rubber gloves to protect your hands from the skin-drying effects of ammonia.
Mix 2 tablespoon of ammonia with 1 gallon of warm water in a bucket, and then saturate a clean cloth with the ammonia solution. Use the ammonia solution and cloth to remove any remaining staining substances, stain odors and stain pigment left by the original stains. Gently scrub the wicker to remove the stains without damaging or breaking the wicker material.
Empty your bucket of the ammonia cleaning solution and rinse the bucket with plain water. Fill your bucket with cool water and use the water to rinse your wicker furniture. Rinse the furniture repeatedly to wash away any remaining stain residue and the ammonia cleaning solution.
Dry your wicker furniture outdoors, out of direct sunlight. Allow the furniture to dry completely to avoid the formation of mildew.