One might add fine powder; more often, one removes it (6)
I believe the answer is:
duster
'one might add fine powder' is the definition.
(someone who dusts)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for duster that I've seen before include "cleaner" , "yellow cloth" , "Cloth for cleaning chalk from blackboard" , "Soft cloth for cleaning surface" , "Rusted (anag)" .)