grataku,
I'm interested in the site, but haven't been able to link to it yet. This PC (at work) keeps looking at me cross-eyed when I try to go there.
However, whilst I'm waiting to get through, two things that work well for cleaning and/or surfacing Al:
1) Ordinary sandpaper. Aluminum is a fairly soft metal; it's not hard to sand. Anywhere from, say, 50 grit, on up to about 220-320 grit will give you a range of 'brushed' finishes. Surprisingly, the coarser end of the spectrum (80-100 grit) will give you a surface about like you're accustomed to seeing on 'real' gear. I would have thought that it would take finer grits, but this is something that I've played with off and on. Use even pressure and long, straight strokes. Even one curved or hooked stroke will show against the light and take several more strokes to erase.
2) Sodium hydroxide (aka Lye, Drain Cleaner, etc.) leaves a very nice, soft looking, matte finish on aluminum. You either like the result or you don't; you only get the one result. Ten or twenty minutes submersion in a solution of 1 tablespoon sodium hydroxide/1 quart water will do just fine. Sometimes I use 2 tablespoons. Use a plastic or glass container--do not use a metal container. Glass baking dishes work nicely. The reaction will be slow to start. Do not heat. Just be patient. You will get hydrogen gas, so no smoking and no candlelit dinners, even though the amount of H2 given off is so small as to not support prolonged combustion. In fact, you'd have to work at it to get it to light in the first place, but play it safe. When you're done, pour the rest down the drain and get a clear drain as a fringe benefit.
Both of these techniques have the advange of being cheap. Use normal precautions when working with sodium hydroxide, as it's not mother's milk, but it isn't going to climb out of the container and bite you, either. Just use your noodle, okay?
Note that Audio Research uses brushed aluminum fronts with no anodizing as far as I can tell. If you happen to like that look (I prefer black or gold, myself), you can do it cheaply and quickly at home with option number 1. I use #2 for the aluminum ground plates I make to link the big bulk caps in power supplies. There's no reason not to use it for a face plate.
Back to trying to get to the anodizing site...
Grey