I have used an electrolytic process for rust removal which works
quite well.  It will remove all rust but leave the metal a dark color.
This 'blackened' finish can be washed off or polished out easily.
This method is safe, cheap, easy, and can be used in many different
ways for different size pieces.

Go to http://www.bhi.co.uk/hints/rust.htm for more info.  Do a search
for "electrolytic rust removal" and you will find several sites like
refinishing.com and metalsgalore.com that will have information on this
process.

Mike Frost
Manassas, VA