Apparently my sign - "I'm retired; stop asking me to do things." - is not very effective, as I haven't had nearly enough opportunity to work on this project this week. I fear it will be summer before I can finish. If so, at least it will be ready for NEXT winter.
After soaking for several days now in the Simple Green solution, the cans seemed quite clean as I carefully removed them and placed them in a couple old wire milk cases I happened to have stashed away just waiting for such an occassion. I say "carefully" because they are quite fragile as you will see if you "try this at home".
In case you do try this, I'll mention a couple more suggestions. First, if you drill them out like I did, leaving a sort of "lip" on the bottom end (see picture just above), remove them from your cleaning solution bottom-first so that any aluminum shavings wash out as the solution drains out the top.
Secondly, as the picture above shows, stack them bottom-up for good drainage. Otherwise, water will collect inside the bottom lip and will prolong the drying process.
Once I had them packed into the milk cases, I thoroughly rinsed them so that there would be no residue to inhibit paint adhesion later.
I included the above picture to show you - hopefully - the aluminum shavings remaining in the bottom of the cleaning solution.
The next planned step is to "glue" the cans together into 12-can tubes. Doing this next serves two purposes. First, as mentioned earlier, they can be "curing". Secondly, I can measure one of the stacks to double-check my design dimensions for the frame that will house the collector tubes.
Thanks for looking.