@Karl-D dry shampoo will create too many noises , unless you use it on dark hair and beard in body mode , but baby powder works better . You can also use white hair spray for fine layer
For objects that can be washed and are no porous, I use also Temporary Marker, it creates very light layer and dry quickly , then after scanning just washing off with water ,great for black plastic , metal parts, shiny ceramic , glass etc…