Helen,
Well, I'm glad it isn't Eastern filbert blight. I think it must be some type of scale insect. When you peel off the 'shell', you are only seeing the 'fluff' that remains after the scale insect has moved on. I would still go with the directions for cleaning up and use a horticultural oil in early spring.
I don't know where you are located, but if you are in the US, you could contact your local extension service for id. If they give you suggestions for any pesticides, let us know and we'll see if we can find something environmentally friendly.
http://www.ceinfo.unh.edu/cesites.htm
If you aren't in the US, maybe taking a sample, in a sealed plastic bag, to a large nursery would be helpful.
Newt