Wash the wicker furniture regularly with soap and a sponge. Fill a bucket with soapy water and wipe down all surfaces. Regular washing will prevent the buildup of mildew and can remove any accumulated dust or debris. Washing the wicker is also the first step you must take before applying a coat of paint.
Hose down the wicker after you have wiped it with the soapy water. If you do not have a hose, you can rinse out the bucket, refill it with clean water, and pour the water over the furniture to remove the soap suds and the grime. Allow the chair to completely.
Apply a deglosser to the wicker. Deglosser is available at most home-improvement stores. Deglosser will better enable the paint to adhere to the wicker surface. Follow the instructions for the deglosser and allow it to dry.
Paint the wicker with weather resistant outdoor paint. Most wicker furniture is made of a material called rattan, which is absorbent. Absorbing moisture from the outdoors and the weather will eventually cause the wicker to deteriorate. Adding a coat of paint will seal the wicker and help to shield it from the elements. Apply the paint with any method you prefer, however spraying is the easiest way to get an even coat over the intricate weaving of wicker. Allow the paint to dry completely.
Cover the wicker furniture with a tarp when inclement weather is expected or when you know you will be away for a long period of time. This will greatly increase the life of the furniture. Constant rain and sunlight on the furniture, even if it has been painted, will speed deterioration.