Wooden comb, do not expose wash in plenty of water, so they are not stratified or warped. Moisten a cotton swab with alcohol solution (or plain vodka) and carefully clean the wood. Body fat alcohol solution, dust, dirt will stick to the tampon. Repeat if necessary.
Metal combs can be cleaned as well as plastic. Just be sure to thoroughly dry the comb after washing. In other forms of rust patina and the thing will just throw out.
If after all your efforts dirt does not departed, armed with an old toothbrush, dip it in baking soda. Rub the surface with a brush comb, trying to touch everything, including the distance between the teeth.
If your used to comb lice (and it is), then it must be disinfected. Soak the brush in a chlorine solution or in a solution of hydrogen peroxide for 3-5 minutes. Then thoroughly rinse it under the tap with running water.
Especially difficult it is to clean the dirt from around the comb, so-called brush brush. They are especially a lot of mud accumulated savings and hair. Try a toothpick or other sharp object to clean off the hair from the surface of the brush. Then prepare a solution of detergent soap with warm water, small amounts of ammonia and hydrogen peroxide. Place the brush there for a while, for example, for an hour. Then remove from solution. Dirt is easy to remove. And comb will look like new.