Oh yes!
I guess I shoulda' mentioned that all the hand sanding and hand polishing happened on the bike wherever it sits.
I only removed the forward pegs et cetera to make it easier to access the cases for sanding.
The entire reason for doing it, at all, was because I didn't want to dismantle the engine or bike for polishing. Heck, I rode it a few minutes after I finished
Additionally, I did not do the upper engine surfaces but I did buff-up the chrome starter motor cover plate with the quad-zero wool...
I stopped at the casing screws adjacent to the starter cover. Kinda' on the case corner, artistically, carefully, where the engine goes into shadow. I guess you could polish the topside (or bottom side which I did not do either...) but it's hard to see and so ... OK.. I'm a lazy bastard...go on say it.
Also, when sanding, I tried to keep the stroke motion in vertical direction where possible. This seems to minimize the visual effect of seeing scratches. If you were to climb on up to the papers in the thousands range, then obviously this would become less of an issue but since I was going more for that satin nickel as opposed to chromed look, super fine scratches are actually what gives the look so try to be observant of this as you work through the process. Vertical seemed to be harder to see...
I've not heard about steel wool and alloys?
I guess it's possible these cases are actually "aluminum" but I've always assumed they were an alloy of AL and other metals for strength and exposure to ... the street use they see.
I guess I don't believe triple and quad zero steel wool could become trapped in the alloy...
I did have to sweep off the "black dust" (seen in close-up pic of front wheel, on garage floor) occasionally but ultimately the alloy is hard and shiny smooth but If so, then maybe skip the steel wool if you're worried and just press-on with higher grit papers. By the time you hit the thousands, you're polishing, not sanding anyway...
I'll keep this thread updated over time but ultimately I've used triple and quad steel wool for so many years in other restorations (auto glass and chrome, bike chrome, home renovations). I used it to restore mid-century, aluminum window frames on a house with great results. Now that rusted because I forgot to clean-off the dust and it rained one night. Had to redo one whole window frame to clean it up.
So maybe a vacuum would be a good extra tool to have but I found most of the black dust fell off directly except around engine case top area... This area needed brushing (I used a small soft bristle dust pan brush...) or shots of compressed air (mechanical and human).
Scotchbrite pads would be useful too! No doubt but honestly, I didn't think about them so I guess I can't say for certain where in the process they would be best since they start off as being more abrasive and with use become less so. By the time you're hitting it with 800 grit paper, you're close to what your wife uses on her fingernails but definitely scotchbrite pads would be useful in this process for sure.
Lastly, I guess it's worth noting something about this. It will have an on-going maintenance requirement. Probably no different than washing the bike but in effect, the stage I took it to (so called satin-nickel finish) is in effect more raw or... porous than it was from the factory. This means for example that ... grease or oil will appear to stain it (I'm doing valve shims this week...). Once that happens (any kind of chemical/oily stain), you'll have to re-surface it - your highest paper and quad-zero. I've done it twice now. The steel wool by itself wasn't enough to remove the oily finger prints (carb removal/installation) but scuffing it again with 800g and then 4-0 wool did. I reckon you could always spritz the areas with clear coat or similar if you're worried but to me the whole garage and it's contents entirely are one bit maintenance concern which I enjoy...ain't that why "the man caves" on HGTV always end up in the garage?