How To Clean Wicker Furniture
Here is a step-by-step approach to cleaning outdoor wicker furniture:

Vacuum
The first step in the process is to use a handheld vacuum to vacuum away the dust that forms a thick coating on the surface of the furniture. If you are cleaning the furniture after a long time, be prepared for loads of work; roll up your sleeves for what you should have done for a long time and kept postponing (procrastinating)!
Brush
The next step is to get rid of the dirt that gets stuck between the wicker and the crevices. Use a new, soft bristled paintbrush to dry brush all the surfaces. The brush is useful because of the fact that it can go between the gaps in the wicker weave and can loosen any dirt that is stuck on the wicker. Do not neglect the back and bottom of the surface of the furniture.

Wipe With Dry Cloth
Dip a clean cloth into a bucket with a mixture of water and mild detergent. Wring the cloth so that it is damp, not dripping. Then wipe the wicker surfaces. You will have to begin at the tightest woven sections and make your way to the loosely woven surfaces so that the dirt does not get trapped into the tightly woven areas.

Use Soap
In the next step, you will have to clean your wicker furniture using mild soap and water. It is best to take the furniture outside and hose it off using a spray attachment. You will, however, have to be extremely careful not to disturb the wicker weave pattern while the furniture is wet or you may cause permanent damage to the shape of wicker.

Wipe Dry
With a soft dry cloth, wipe every end of the furniture, being extremely cautious about the ends. The weave will be very vulnerable when wet but will become firm again when it dries out. So, till the time it is wet, you will have to work with extreme caution.

Dry
After the furniture has been wiped dry, it needs to be kept in the sun to dry out completely. If you begin to use it before it is completely dry, you will have to deal with mold and other kinds of fungus.