It’s been awhile on this one but I did get back to them recently and I thought I share what worked for me.
In the end it was fast (about 10 to 15min on each one) and simple. Scotchbrite wheel on a drill. I used the one pictured for the bulk of the work and another same diameter but thinner wheel the do between the vents. Just held it on a bit of an angle and it got in there really well.
Picture looks a bit like they’re polished but they’re just clean and the Scotchbrite wheel re-grains the aluminium really nicely. It won’t get rid of the deep battle scares but it’s a big improvement on what they were.
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