With a torch and a wire brush. Then a 3M ROLOC "Surface conditioning disc" will remove what is left off the metal.

Brian

 

If you have sanded on it and it's still copper colored,it is NOT brass.Brass was used generally on tops/sail panel joints,structural joints and IF it IS brass.You best leave it and just clean and filler over it because you'll not find a better joining material.
Pic/s would help.

 

I haven't sanded on it, just scraped the paint and seam sealer off. Im not sure what metal it is, its just brassed colored. I have to remove it though so I can seperate the quarter panel from the car. Ill try and get some pictures of it.

 

Is there an outside chance that it's origional to the vehicle?

But if you absoloutly feel that you must remove it, What MARTINSR said is what I'd do.

 

Yes, it is original to the vehicle and I would like to save one of the panels at the joint if I can.

 

Took me a while, I kept forgetting to get a picture. Here is a picture showing the brazing I need to remove. The panel I want to save is on the right side.

 

I would cut out what you want to get rid of and use a 3" Roloc sanding disk on a small hand held grinder.

 

It could be factory....when I worked in an AMC plant in the early 70s, we used to braze certain joints that couldn't be spot welded.

 

It is factory, that is exactly how it was on the car when they cut the quarter panel off and nothing had been done to the car as far as I could tell.