My DT3’s sliders are pretty grungy. I thought i saw a post where someone used emery cloth side to side, then clear coated? 
I would prefer the factory look to a super polished look (if my memory is correct, weren’t they the “brushed “ look when new ?).
 I would appreciate any advice on materials/process.
TIA

My experience says you’re right on target. I used various grits of sandpaper depending on how deep gouges are. Fine sandpaper and ScotchBrite pads. The gray is equivalent to about 800 grit I think. The finer you use the shinier it gets. Finish off with careful side to side motion to mimic original finish. I used 2K gloss clear. Pretty happy.

Thanks Pedalcrazy! (From that username, you must be an electric guitar player?). Is 2K the brand name of the clear?

Did a little digging, looks like SprayMax 2K is the clear?

These are NOS fork tubes. They have some minor scratches and a couple small areas that corrosion has gotten under the clear coat. But from 5 feet away they look good.

For really bad aluminum parts I send them to a vapor blaster. Then depending on the finish I want I'll buff and polish. Some parts I think are good enough to not clear coat.

For buffing and polishing slow is better. This variable speed JET can be set between 900-3600 rpm. I run it at 900 rpm. The wheel on the right is from TP Tools item # 8455-87. Gives a nice finish close to the factory. The cotton wheel on the left will give a mirror like finish with the white rouge stick.

There is also different brands of liquid/paste aluminum polish and 0000 steel wool and Scotchbrite that can be done by hand.

 

 

 

This is way over the top polishing.

 

 

Vaporblasting seems to be used for motor parts so would that make easy work of it. Then clear coat if you want a shiny look. I don't really know & just guessing up ideas.

Just had my forks vapor blasted and it gave a similar look as those nos ones but not quite. Were the engine covers from the factory a similar finish as the NOS forks or more polished than those?

From what I've observed in my collection of NOS parts the lower fork tubes, engine covers, hubs and brake backing plates had the same treatment from the factory with minor variations.
 

Thanks for all the ideas guys! As I recall, the original factory finish was “satin” on all the unpainted metal, not what I’ll call “mirror-like “ like those side covers. I prefer the original look, but to each their own.
I guess the beauty of aluminum is that it’s fairly easy to do it over, which I suspect I will be doing, probably more than once.