That's what I did to mine. This is how it looked after I'd cleaned it. Notice how much oxidation there is.For cheap and easy...spray on oven cleaner does a good job. Just spray it, let it soak for a few, then scrub with a scotchbrite (sp) pad.
Muratic acid (aka hydrochloric acid) will not work on aluminum. It will actually dissolve it and leave a layer of smut behind.i would try muriatic acid. stuff is nasty though, try not to breathe it in