It's been a while since I had to clean wires, but as my fading
memory recalls, the ones I worked on were #4 wire gage.  I acquired
the appropriate [steel] nut and cut through one side as in the
letter 'c'.

I squeezed one edge in a little thereby making a die to clean the
threads.  Or was it that I expanded one side.  One or the other --
as I said, fading memory.

Regards,
Jon Page