horns-78 280z

Continuing to clean up and refurbish a lot of the smaller items on the resurrection project so when assembly time comes the components will be ready to install and work.  The horns and brackets are quite rusty.  Bench testing the horns with jumper wires -positive to spade terminal, negative to clean mounting post-produced no results.  Took one of the horns apart and very surprised how clean everything looked inside except for the green corrosion on the two contact points.  Cleaned and reassembled but no results.  The contacts are both tight together on the spring arms.  Any helpful tips?  The tension adjusting screw did not want to move easily so I left it where it was.  Thanks for any help-John-Lugoff ,SC.  Aftermarket horns are not very expensive but thought it would be neat to get the originals working.