I think it's a very good home remedy for the average Joe's workshop. Not a very strong acid and very easy to get, just 'borrow' from the kitchen.
I have now used it for zink plating, refurbishing of Amal carbs for my Norton and lately a rusty camshaft.
I just had to try it, but because of the New Years party and other things I forgot...
Anyway after a couple of days I removed the camshaft from the acid. And this is how it looked before polishing the surfaces.
I just put one end in the acid, this is how the other end looks like.