My wife picks up eye shadow at the dollar store and I think it would be great for weathering. I seem to recall an article in either MR or RMC a couple of years ago that talked about eye shadow weathering.
I just scrape the sides of pastel chalks to get what I need. Placed in a water color pallete and then applied with a stiff bristle brush, I seal it with Krylon Matte Finish.
That was funny. Ive been searching around and I think I will be using an assortment of items. I will try some of the AIM Products powders, some of the Reeves Gouche watercolors, and a splash of Rustall. It seems from the pictures I have viewed that each of the items add there own special touch and combining the watercolors with the powders gives you almost unlimited options. We shall see.