I decided to use the tumbler method for cleaning my bolts/nuts. I don't have the patience to individually clean each bolt head.
I bought a tumbler from Cabellas (any major hunting store will have similar tumblers):
Media -I used corn husks, didn't feel it necessary to get too abrasive:
Polish- Flitz also from the Cabellas:
I loaded the tumbler with the dirty bolts:
Here is how they came out. The heats are all great, well polished, not remnants of dirt. The threads were cleaned of major debris, but some leftover thread lock still remains. This has no effect on the looks after wheels are assembled so I don't fuss about it.
The bolts which were caked with brake dust:
After, they came out good. Again, they are hidden so perfection was not important.
Hopefully this helps people in the future. I wasn't sure which method I was going to choose to clean the hardware, but the more I thought about it the less inclined I was to manually do each bolt and nut. I left the bolts to tumbler for 3 hours (doing one wheels worth at a time), and the nuts were in for about 5 hours (all at once).
Overall cost for supplies was just under $100. The tumbler will likely be used for many future projects to clean up other hardware as I see fit.