Keeping it in dustcases does make a huge difference. My personal preference is zipper binders. They are a lot cheaper (especially if you buy them on clearance) than binder/dustcase combinations, but a lot of collectors probably do not like the look of zipper binders. I keep parts of my collection in about 30+ zipper binders.
If you already have dust sticking to the Vario pages, I find that used fabric softener sheets do an excellent job of removing the dust and keeping the dust off until you can put the Vario pages into sheet holders or into a binder with dustcase.
Just remember that they should be USED fabric softener sheets. DO NOT utilize unused fabric softener sheets. I've never tried unused fabric softener sheets, but I would think they are too saturated and would likely leave some sort of residue. I've yet to see any detrimental effects from the used fabric softener sheets -- but I'm only wiping the surface of the Vario pages with NO stamps exposed.

k