Water once in a while will not damage the heads, and they can be washed if they become dirty. Protect them from liquids which stain and do not store them in direct sun, as it overly dries and ages the skin.
Drums relax their tone as the humidity in the hide increases.
They can be temporarily tuned higher by warming the head, which dries it out. Never get it hotter than is comfortable to touch. A paper showing this method in detail is included with each sale. Peg drums can be tuned in the African style, by tapping the pegs in or out with a hammer or stone. They can be completely removed for safer shipping.