Which abrasive to use ?

[PJB]

Oh for sure bead blasting can warp your parts. 
We have something called a
 “bronco blaster” at work used to even out the finish on aluminum castings.   It a chamber that slings huge volumes of small steel shot at the parts on a rotary turntable.   Theres a timer used to adjust how long and aggressive depending on requirements.  Leave something in that sucker a bit too long it will turn it to a pretzel.
Sometimes they have to flip the flat plates to reverse the warp out.

[woodchucker]

I guess I have never been aggressive enough. I use walnut, and glass bead.
I don't have a cabinet, so I lose all the media, I just shoot outside with a mask, and a shield.
it goes fast, so not too long.

[PJB]

Looks like what you did worked fine. 
Scotchbright pads are another option I sometimes go with for cleaning.   Not great for heavy paint or rough surfaces but for stains and light rust it works pretty good.   The abrasive grit in it gets everywhere so thorough cleaning and oiling afterwards is good idea in the case of touching up sliding surfaces.   I wouldn’t recommend scrubbing machine ways down with it other than maybe one time for restoration clean up.   Its abrasive so your balancing the benefit of cleaning with introducing more wear albeit small.   

Off topic further only as point of interest Dry ice is a gentler media option but not practical for home/hobby.   For one the air volume required is huge like 50scfm @100psi.   We used one for a bit but the other issue was the disappearing bulk media.  After less than a week even in an uber insulated gaylord the stuff would evaporate away.   

[chips and more]

You folks can figure out which blasting media to use. For me, I choose this!!!

https://www.youtube.com/watch?v=Qjj6SadiJO4

No air compressor needed! Just big bucks. But you sure would be the best friend in town, if you know what I mean.

[PJB]

I know seriously.  Every time you turn around lately if there’s a problem hit it with a laser!   

[Jake Parker]

The sticker shock!!