Do NOT even attempt to clean dust off that eInk screen. The slightest pressure could destroy pixels. It is not like the touch screens on the Sony PRS 900 or the iTouch. They have a special screen coat which protects them
I wipe the dust off my screen with a microfiber cloth all the time; I've done so for two years and there's not a scratch, blemish or dead pixel on it. I don't think the screen is quite as delicate as you make it out to be. I even dampen it when there's a spot that won't wipe off easily.