True wicker is made of rattan, reed, willow, and bamboo. It should be kept away from direct sunlight and excessive heat. Both will dry it out, making it become brittle and cracked. Too much dampness can cause mildew.
To clean wicker, vacuum it thoroughly and use a brush attachment to remove dirt and dust. Then scrub with a soft-bristle brush dampened with mild soap and water. Work carefully to get between crevices to remove collected dirt. Following a good cleaning, let the furniture dry completely.
If it has chips or scratches in the paint, sand lightly with very fine sandpaper. Wipe the surface with mineral spirits, then apply two coats of quality paint. Regular care includes dusting with a feather duster. To avoid its drying out, dampen it once a month with a fine mist of water from a spray bottle.