I like to hold them in a vice and use a wire brsuh on the end of a dril, l find a bench mounted wire brush tends to take your fingers off, then I run a die down it to make sure the threads clean
If you are only doing a few, the wire brush is prolly the quickest way, but if you are doing a whole engine's worth of nuts / bolts then the electrolysis bath is a much better idea (given a big enough bath you can do ALL the parts in one go, and leave it while you work elsewhere).
Also, if you really wanted to, you could do an engine block that way too.
Actually, That just made me think......while we are on the subject of anodizing ally parts, has anyone anodised a mini GEAR BOX CASING??
That might look really good on a show car, for a touch of colour!
As long as you only did the outside of the casing, it wont cause any problems with tolerances (for those who don't know, anodising will increase the thickness of ally parts a small amount, due to the build up of the oxide layer).Oh, and I just remembered a way to clean up grotty ally parts to clean smooth metal - steep them in a *hot* bath of cheapo BIOLOGICAL washing powder / liquid, the enzymes react with the dirt and loose oxide layer and dissolve it back to clean metal (but does not damage the ally or the protective layer of oxide)
I have used this trick on a load of aluminium tubes and rods that had been left outside for years, did a great job when left overnight and only required a minor scrub with a plastic pan scrub to make them shine.SS
