John, I actually asked one of my instructors about this technique
recently. ALthough I have not yet tried it you might have some luck
using a mortar and pestle (like for grinding herbs/nuts etc) to make
the rouge into a fine powder.
Also, as odd as it sounds, try plain old white toothpaste (not the
gel kind) it works well.
Out here in Singapore we get very creative with tools.
cheers-
Carree