You didn't bring the outdoor furniture inside for the winter, or even cover it. Now, your chairs and patio table, even the umbrella, look plug ugly. No need to panic, though. Just give them a good cleaning, maybe even new paint, and they'll look fresh as spring.
Whither the wicker? To clean woven furniture, you'll need to get into and around those intricate weaves. And that requires a variety of brushes -- a new, rather than used, toothbrush (stiffer bristles); a small paintbrush with bristles cut down by half, to make them stiffer but not sharper; and a bristle brush with medium bristles. Some experts recommend sharpening a dowel to pick out bits of dirt and debris, but the best tools are already sharpened -- the wooden skewers used to make shish kabob.
After you've gotten the gunk and grime out of the weaves, vacuum a wicker piece thoroughly. Then wash using minimum amounts of a solution of two tablespoons of ammonia to two gallons of water. Clean in sections from top to bottom, then dry the wicker quickly to prevent it from warping. Lay the piece on a clean canvas drop cloth; tip it so the tighter weaves are on top and the looser on the bottom, so the moisture runs down and away quickly. Keep the weaves straight, so they don't shrink.
If mere cleaning isn't enough, sand and repaint (follow the manufacturer's suggestions). Depending on the piece, spray paint may give better coverage in faster time.
Attend to the aluminum: For regular aluminum chairs, grab a plastic scrub brush and dishwashing detergent at full strength and then scrub, scrub, scrub. Rinse thoroughly, then let dry.
For coated-aluminum pieces, experts also recommend full-strength dishwashing detergent, using a sponge instead. Rinse completely, dry with a soft cloth, and then rub on car wax to polish, avoiding the fabric. If you get wax on the fabric, clean it quickly. Buff the metal after it dries.
Ponder the plastic: Take a look at your old plastic furniture. Is it worth keeping another year? If the chairs cost $2 each 10 years ago, you can find sturdier and nicer ones for about the same price today. But if you opt to keep them, wash the pieces with three tablespoons of powdered laundry detergent (or oxygenated bleach such as OxyClean) mixed in a gallon of warm water. A scrub brush will work, but avoid stiff bristles, which can scratch or gouge the plastic surface. Let the solution soak in for a few minutes. Rinse thoroughly, then dry.
Cleanse the cushions: Check the label for the manufacturer's suggestions. If cushions or seat webbing are washable, use warm, soapy water or a foam cleaner. Apply with a sponge, rinse and dry quickly.
Repair the rust: Wrought-iron furniture tends to rust, which is why it should always be covered if left outside in winter. If corrosion has already begun, use a wire brush on the metal lightly, to remove the rust but not the paint. Naval jelly, available at home centers and hardware stores, also can dissolve rust; some products become a primer that lets you apply protective paint in 24 hours. Rust stains can be removed with fine steel wool dipped in kerosene. Wear protective gloves and safety glasses and apply in the open, away from fire. To get into the joints, disassemble the furniture.