For reducing dust in aspen I made up a 'sifter' with window screen, Just put a small amount on the screen at a time and shake, tap then place good stuff in tank or clean bag and WHA LA you go dust free aspen. It is time consuming but you seem like the type to take time to do things right.

Just an idea that popped into my head, you could speed up the process a lot by using a vacuum with a screen...