If it is not fastened in place take it outside and hose it down. I would not like wicker in bathroom for the simple reason it is hard to clean and flushing the stool puts out a spray of dirty water for so many feet.

I always sprayed my wicker down with a garden hose too. But I didn't clean it but once a year.

"I always sprayed my wicker down with a garden hose too."

same here. I picked a shelf up at a garage sale, hosed it down (using a brush also), let it dry and then spray painted it.