Cutting aluminum with a miter saw and nonferrous blade is the best method for getting a clean, straight cut.
An angle grinder fiber chop saw wheel may work, but it will likely get clogged and stop working, since the soft aluminum coats the abrasive fibers on the wheel. A hacksaw or metal Sawzall blade can be used, but it usually leads to irregular cuts, especially on angled cuts.
A "non-ferrous metal" blade is a toothed circular saw blade designed to cut soft metals (but not steel). The high tooth count of carbide teeth lessens vibration, creates finer shavings, and prevents snagging of the metal.
Cutting metal with a toothed blade can be dangerous, so be sure you're wearing safety glasses and make sure the workpiece is clamped or held firmly in place.
If you start your cut too fast and the piece isn't clamped down, it may get caught in the blade, which will at minimum hurt your ears, and possibly other appendages.
Be sure that you aren't starting a cut on the edge of a piece that may get snagged by a saw tooth.
For example, when cutting an Ultralox bottom snap (which has a U-shaped profile), position the snap with the open part of the U against the saw fence. This way the teeth won't get caught on the edge of the U profile.
Anytime you're cutting with a rounded piece against the saw, be sure that the workpiece is braced so that it won't rock or move mid-cut.
This is especially important when making angled cuts like on a stair panel, because it will throw off the angle of the cut.
