I don't know about stripping painted wicker furniture, but if you want to paint it another color you should probably spray it with a spray on primer before you spray it with regular spray paint. If your wicker is painted a glossy finish I would definately use a coat or 2 of spray primer. Be sure it is primer. It will keep the regulat spray paint from dripping as much. Just remember to spray it a little at a time. Antique people would know how to strip wicker, but I bet it would be a pain in the butt to do. There are a lot of strippers out there, so you may find one that will do it for you. Good luck!