brushed aluminum is another easy to do effect. all you need is silver paint, black paint and a stiff bristled paint brush (i use an acid brush). all you have to do is lay down a medium wet coat of silver then right away drag the paint brush though it in a straight line. it scraped away some of the silver and causes transparent spots and spots with no coverage. then let it dry and back it in black. the more you drag the brush though the silver the more distressed it will look.
here's the back of my stadium truck body with the brushed aluminum done (just ignore the pen scribbles they are on the outside of the body and are marks to let me know where to add shading) . it'll give you an idea of what it looks like and how to use it.
just a few pointers to keep in mind.
don't get crazy with the paint. light coats will work better and last longer.
use a quality masking tape or liquid mask. the cheap stuff just bleeds and can leave sticky residue on the body.
make sure you use sharp hobby/razor blades
take your time and don't try to exceed your skill level.
buy a blank sheet of lexan to practice on. a 12"x12" blank is less than 5 bucks. better to mess that up trying something new than a $25 body