So I have had a few customers mention rust on their smooth rods, and this is common when dealing with Drill Rod. Drill Rod is hardened and is also drawn to a precision tolerance. The composition of the alloy is a more important factor than any sort of plating. Typically hardened tool steel is a high carbon alloy with chromium and molybdenum as well as manganese and other elements.
Here is a solution I have found to work for me, below I will have a short pictured tutorial showing what type of sand paper to use and how it should look once your finished.
Sand Paper I used( as shown to the left) was P150. I’m not real familiar with automotive sand paper and their gauging system but I’m sure if you can find something even finer, you would get great results..
I recommend dry sanding with something AT LEAST this grade. I simply sat on the floor(Indian style) and slowly rotated the rod with one arm while the other was sanding.
After you have them sanded down, I recommend coating them in some lubricant and wiping any left over sanding debree ([PROTIP]A sugar free Rockstar may also help this procedure.)
You should end up with a nice finish like this here: