Same idea--used the cans (ran through the dishwasher) and I covered them with brown craft paper. We used thicker paper first to make our patterns, and then traced them onto cardboard and cut them out (lots of whining here about how hard it is to cut cardboard). Finally we used the regular playcolor sticks to paint the pieces and glued them on.
Each student had a can of their own, and the last day they had art we raised our totem poles and had a traditional Potlatch party! The last day of art for the year is a little wild anyway, so why not just roll with it and let it get loud? If you can't beat 'em, join 'em, that's what I say!