If the chain is grimy, clean it by brushing with a citrus-base solvent and wiping with a rag. Then finish the job with soap and water. Rinse the bike with a hose or pail of clean water, but don't direct it at the headset, bottom bracket, hubs, or pedals because water can enter their bearings and cause damage . If you can't get the rim surfaces completely clean, try a solvent such as acetone or sand them with emery cloth. Look at the faces of the brake pads, too, and pick out any pebbles or deposits with an awl so they can't score the rim.
Inspection Check the spokes and rims for break or cracks.
Check the tires and brake pads for baldness. Check the grips or bar tape for slipping, cracking, or peeling. Study the cable housing where it enters the brakes, derailleurs, levers, and frame stops. Squeeze and hold the brake levers to see if the cables are rusted or frayed anywhere along their run. Also measure the chain for wear.