Hello,

I use "Naval Jelly" available at hardware stores.  I think that the active 
ingredient is phosphoric acid, and there are other brands to choose from. 
 The process doesn't remove the rust, but converts is from red iron oxide 
to black iron oxide.  The black is stable and doesn't flake off.  So, it 
stops further rusting.  It is also compatible with most paints ... read the 
label.  Of course, when painted, it will still look like painted over rust, 
since the rust wasn't removed.

Mike

Michael A. Radtke  -  Z74               Voice: 602-862-4897
Bull                                      FAX:         4853
13430 N. Black Canyon Hwy.
Phoenix, AZ  85029                      Email: m.radtke@bull.com