Assuming that your work is wide enough, start by putting a one-inch cup brush into your rotary hand piece. If your stone finish is truly good enough, a diamond compound in the nine-micron range will work like magic; however, don’t feel bad if the nine-micron diamond won’t take out the stoning marks and you have to switch to the coarser 15-micron diamond. This just means that you need more practice at creating a fine stone finish.

Experiment with different bristle lengths. The longer the bristle, the longer it takes to cut. The smoother the finish in the metal and the shorter the bristles, the faster it will cut – but you run the risk of damaging the flat-ness of the job by cutting shapes and grooves into the aluminum.

Find a good balance.
Cool the brush only with denatured alcohol. Mineral spirits will make the brush cut much too fast – ruining the job. Be careful not to brush out deep scratches, because you will never end up with a decent flat surface – you’ll end up with a ruined wavy surface. Flatness comes only from a stone; over-brushing will only ruin the flatness. Wood sticks cut to shape can be used in a profiler machine with diamond to lap corners and sidewalls, if necessary. Once brushing is complete, it’s time to buff.