For persistent dust, you can dampen a clean sponge and run it gently over the figurine before finishing with a brush.
For stains, such as those left by flies, a slightly dampened cotton bud can be used with care.
If more thorough cleaning is required, use only soapy water and Marseille soap as a last resort.
Detergents should be avoided, as should cloths and wipes, which can damage surfaces.