Vacuum the wicker thoroughly to remove any dirt between the woven wicker strands.
Put on the rubber gloves and pour 1 tsp. dish soap, 1/4 cup bleach and warm water into a bucket. Fill the bucket until it is almost full.
Scrub the wicker gently with a scrub brush and soapy water. Rinse the furniture until the water runs clear. Wipe the wicker with a soft cloth, then allow it to air-dry.
If the wicker has deep pits, or if the old finish is peeling, gently sand the surface until it is smooth. Wipe the dusty residue off with a soft damp cloth and let it dry completely, or vacuum the surface of the wicker again.
Open the can of polyurethane and stir to make sure it is completely blended.
Dip a paintbrush into the polyurethane and apply a generous coat to the wicker. Make sure to get the polyurethane deep into the ridges between the wicker cane strands. Let the polyurethane dry completely and then add a second coat.