I use one of those Flash duster thingies on a stick. Doesn't do a perfect job, but a quick swipe once a week stops them from becoming revolting.
Once every couple of months whenIcanbearsedorMILiscomingtostay I do them properly with a damp sock over my hand. I have them all round the bay in our living room and it takes me about half an hour to do the whole lot.
I use a stiff 1inch paintbrush to thoroughly dust them. It doesn't really work on the blinds in the kitchen though, which is near the cooker and a bit grimey - think I'll have to bite the bullet and wash them in the shower. And rethink the notion of having wooden blinds in the kitchen too
Blimey! mine are extremely heavy so I wouldn't want to take them down to shower off. I have one in the bathroom which gets wet every day from the shower and it hasn't warped and it's had 10 years worth of splashing/getting wet.