I would suggest, based on personal experience, that the best way to
clean threads on a threaded rod would be to use a thread chaser die.
This looks much like a regular threading die, but it is to be used for
cleaning and repairing threads only.  The die is simply screwed down
on the existing threads from start to end of the threads.  This will
remove all debris and repair any damaged section of the threads.

Best to all of you.
Jim Cook

 [ Hmmm.  What is the description of the threads for leather nuts?
 [ E.g., the pitch diameter and threads per inch.  -- Robbie