Yes. Any kind of wood or organic fiber material dust can attract and hold moisture against metal which can initiate corrosion. I would get a can of odorless mineral spirits from one of the big box stores and put some in a pail and immerse and shake and rinse out each case with with it then let them dry. If that dust is caking due to lube, that should dissolve it unless it is water-base lube. In the case of water-base lube, forget the mineral spirits and go for some dishwashing liquid in water instead. You may be able to get them clean by just shaking them in a milk jug with that solution.
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