Besides removing the visible dust with soap and water, afterwards mist with with a non-corrosive oxidizing disinfectant like hydrogen peroxide.
Or extremely diluted bleach (to a gallon of water add a table spoon of bleach and vinegar each. Do NOT add bleach directly to vinegar or vice versa). That creates greater disinfectant power at a very low concentration. But it doesnt last long (couple hours) so throw away any left overs.
Let it bake in the sun for as long as practical.