I want to paint it black and make sure that it doesnt wear away from the weather.
You may be removing oxidation cause by UV rays from the sunYou might check with the aluminum sales people, or even the manufacturer for a recommended low PH alkaline cleaner that will not damage the finish any further.
pressure washer or if you don't have one you can buy the aluminum house cleaner at homedot or lowes it hooks to your water hose to clean it
muriatic acid water soliune, you can get muriatic acid a a lare hardware store, the only way!
I would use black powder coat to color it blackPaint does not adhere well to aluminum easilyPowder coat is much more resistant to outdoor conditions Rough up the aluminum with sand paper and spray the tool box with Krylon enamel spray paint.
