I use this "tumble" process at work.It is in a vibratory machine that uses a media as a deburring/polishing agent when mixed with a H20 and oil as a lubricant.It does a good job but will leave a pattern type finish on your part and may also remove any grain on a intake.I use it mostly on hot rolled steel and stainless.It will work very well on aluminum depending on media type and duration of the cycle.I don't care for the finish on aluminum though.Very dull..
Steve