I am not an expert, but found this article for you, hope it is helpful.

Rattan, Wicker and Cane were and are quite often painted, generally white. If the piece you have is painted and dirty, it's best to Clean Your Wicker Furniture first, it may be that a good cleaning is all that is necessary to make it look quite acceptable.
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Strip or Paint Wicker

If it still needs help give some good serious thought to whether it (and you) really need to go through the rigors of stripping, or if a light refreshing coat of paint sprayed from a can might do the trick.

A primer coat will cover most marks, then a final coat of paint can be easily sprayed on using spray cans.
Natural Wicker

If the wicker furniture isn't painted, then it probably would be better off if it isn't stripped. If the natural wicker is old and has been finished with a clear finish and it has chipped a bit, you would probably be better off to clean the wicker and apply a new clear finish leaving the chips as they are. If the wicker is stained, then use a good oil stain and touch up where it may be chipped before applying the clear finish.
Any Liquid Stripper Will Work

Wicker, Rattan and Cane require no special stripper. A liquid stripper, any brand, is easiest to use and clean up.

The wicker (I'll use the word wicker as an all inclusive word, rather than repeating wicker, rattan and cane each time) will become supple and loose as it absorbs the stripper, but will tighten back up when it dries.
Handy Tools For Stripping Wicker

Some real handy tools to use for stripping wicker are a tooth brush, a paint brush with its bristles cut to about half the length and a piece of dowel about the size of a pencil and sharpened in a pencil sharpener. The reason for cutting the paint brush bristles is to make them stiff enough to have some muscle, yet soft enough to work into the weave of the wicker.
Clean Before Stripping Wicker

The job will be easier and quicker if you Clean the Wicker Furniture first. You may even find that stripping the wicker won't be necessary.

If the wicker furniture has been painted you probably won't be able to get it back to a natural color since the wicker would have soaked up a lot of color initially and will soak up more pigment as it becomes moist from the stripper, so you would be better off to strip any large build up of paint that will come off easily, then after it dries, repaint with light coats of paint using a spray can.

Be sure to let the stripper work long enough so it will liquefy so you can push it off with your brush, because you won't be able to do any scraping, like when refinishing wood furniture. Tilt the wicker furniture so that the tighter weave areas will be uphill so that liquefied residue will run toward the looser weave and not have a tight place to puddle up.

You'll probably have to go back and restrip some areas, because with a job like this it seems that the residue jumps back on when you aren't looking. Stripping wicker furniture and other wicker items is very tedious and will take a lot of patience, but it is all worth it in the end.
Let The Wicker Dry Thoroughly

After you're through with the stripping let your wicker piece dry thoroughly, at least 24 to 48 hours before finishing.
Spray Paint Your Wicker

Paint is best applied with a spray can, because you can get into all the nooks and crannies and tight weave of the wicker.

Deft brushing lacquer is a good clear finish to use. It gives good protection inside and out. It's also available in spray cans.

Polyurethane is best avoided, as it dries to a plastic coating which is very hard and brittle and will probably crack with all the flexing of a piece of wicker furniture.