Vacuum the dust from hide and hair, wipe eyes/horns/antlers down with a mild soap & water. If insects (moths) are a problem, better get some Protex from Van Dykes.
If they begin splitting, a quality taxidermist can repair it.
http://www.vandykestaxidermy.com/product/01319078/
Protex Mount Care
$59.49
Item no: 01319078
1 Gallon
Protex Mount Care protects hair, fur and feathers from moth and insect damage. Not only is it safe and easy to use, but it won't wash out either. It can be used for new mounts or existing ones. Wipe the product onto the hair or add it to the sawdust in a fur drum. Protex Mount Care is not water-soluble.