Picked this up a while ago.  It's a J.I. Case Threshing Machine Co. turnscrew that measures over 2ft long.  I couldn't find much on the net about old Case tools.  Or at least ones marked like this.  Anyone see one before or have any information on it?  Also, should I leave it in this condition?  I usually clean up the stuff I buy unless it's rare or in original condition.

I prefer to do minimal cleaning on tools.  Just enough to get the dirt & other buildup off, but leave a nice smooth patina on everything.

That is in near perfect condition. Beautiful piece! I like the patina. Maybe just a very light cleaning of the "rust"?