You can fill out the bigger one, than clips the smaller one. Can you give me an example with the clip? I can't get it work in a way I want to have it. I've found another thread here: http://www.tug.org/pipermail/metapost/2006-September/000650.html But I fail to see the conclusion there too.

And alternately, you can construct the path of the difference out of the two circles, and fill the constructed path. As for the path of the difference, how do you mean that? Example?

Adam