Since There are no responses.. I try to put some guts to deal the dust with Rodico.. Using a toothpick and wrap the rodico to the end of the tip, gently push down and up, the rodico doest his works.. Not all can be extracted and I think I have get rid around 30% of the dust.. Sometimes even touch the lume pot and the lettering but they hold to the dial quite strong..
Here are the result after works.. Some dirt are from the glasses.