The best way to keep your wetsuit clean is to wash it after every use. This will keep it clean and keep the smell away. Make sure you don’t use and chemicals, soaps, detergents, bleaches and things like that for cleaning your wetsuit. All you need to do is to rinse it with fresh water after every use. Once in a while like every few months you can clean your wetsuit with a special soap for washing wetsuits. Also check this – how do you wash your wetsuit.