an excerpt from ScubaDiving Magazine. I use a wetsuit shampoo and follow the directions below.
Soak It
As soon as you can, soak your wetsuit in cold or lukewarm fresh water (hot water can cause the suit to lose flexibility) with a mild solution of baking soda or wetsuit shampoo. using a mild detergent will keep the neoprene from taking on an odor. soak for about 30 minutes. Turn the suit inside out and let soak for an additional 30 minutes.
Scrub It
During the soak, scrub zippers and velcro patches with a toothbrush. Work the zipper car up and down to dislodge any dirt.
Rinse It
After soaking, give the suit a thorough rinse, inside and out.
Inspect It
Look for tears or gouges, especially along the seams. If necessary, resew the nylon with heavy polyester thread, or repair the neoprene with wetsuit cement.
Hang It
Turn the wetsuit inside out, and hang it on a flat hanger out of direct sunlight. turn it right-side out and repeat.
Store It
Store it on the hanger or loosely folded, and keep it where the temperature is consistent.