I just fixed one of my horns

[Hammond68]

I just took one horn apart and got it blowing again. Very simple operation. I used a dremel,ground off the rivets. Inside is a metal diaphragm. It was rusty, cleaned it up with emery cloth and little wire wheel on the dremel.
There's also a points looking contact in it. It seemed stuck. I pried it apart and cleaned the contacts with emery cloth. Pretty much cleaned it everywhere in there. It started raining before I could get the second horn off. I also sealed it with sealer as it had a paper gasket.
Very simple. In one parts catalog they go for 100 for the set. I can take a few pics of the next one if anyone's interested.
My horn problem was the horns themselves.