FWIW, I made a pen out of solid brass once (slimline) and used a black crome kit from Woodturingz. I didn't like the look of the brass and black, so I, on a whim, buffed off the black chrome with a buffing wheel charged with jeweler's rouge. I also buffed the brass with it.
All the black came off nice and left a shiney silver whatever-it-is metal. It did has been sitting, not used much, for nearly 2 years now and the silver still looks good and the brass looks like 2 year old brass (I didn't have any powdercoating ability).
Give it a try. Use those kits to make weirdo pens out of weirdo material and stretch your brain. Have fun. If something turns out cool, make another one out of a good durable coating (the ti gold or chrome or so) and sell that puppy.