With guidance from the Galooterati, last Spring I was able to de-rust a 
5 gal. bucket of old horseshoes to my satisfaction.  Now I'm having 
trouble with smaller batches of rusty metal.  I have these adjustable 
marking gauges (thanks Ed!) that need a bit of cleaning.  I've 
disassembled them placing the screw, spring and pin in an empty tuna 
can.  I then placed the ruler on edge crosswise in a plastic container 
just long enough to allow that then laid the upright traveler piece on 
its side, not touching the ruler, in one corner and the can of small 
bits in the opposite corner.  None of the 3 pieces to be de-rusted touch 
one another but they are not suspended either.  The ruler blade, 
traveler, and small parts tuna can each have a spring clip with copper 
wire soldered and clipped on each piece.  I have 2 short rebar pieces 
with a single piece of copper wire with clips attached and clipped to 
the rebar.  The positive (+) lead from my old time battery charger is 
clipped to the wire running to the rebar.  The negative (-) lead from 
the charger connects to the 3 copper leads that have been twisted 
together.  The container hold a little less than a gallon of water to 
which I added a tablespoon and a scosh of soda carbonate washing powder.

I'm having no success after 2 overnight soaks with the battery charger 
set for a 12 volt 6 amp charge.  What are the likely causes of my 
failure?  Do the pieces have to be suspended such that no part touches 
the sides of the container?  Do I have the polarity correct (positive to 
sacrificial rebar and negative to pieces to be de-rusted)?

I checked all my fittings before the second attempt.  I'm seeking your 
input before I let the parts soak overnight tonight.

Thanks for your advice;

Bob Hutchins
Temple, TX (a southwestern US state, Jeff)