Diagnosing Source of Oven Issues

When I pulled our double wall ovens out so I could move the electrical wiring and to re-finish the cabinets I was surprised to see scorch marks up the back of the oven and along the wall behind where it had been.  At first I considered taking the ovens straight to the Junk yard; however, we are not ready to replace the ovens yet and we certainly don't want to be without an oven for any longer than necessary.

I decided to explore the burned area of the oven to see exactly what the issue was.  I certainly don't want to re-install something that's a fire hazard.  So here is what I observed:

From this I couldn't tell what happened.  I just knew it wasn't good.  When I looked through the holes I saw wires.  I also thought I saw melted metal; however, when I looked closer it just looks like really scorched metal.

There were just a handfull of sheet metal screws holding everything together so I decided to take stuff apart.  It was actually quite easy.  

Once I removed all the protective metal I saw what looked like the base of a light socket.  The light socket itself looked to be in good condition.

I inspected the wiring and despite things looking a little smoky, the insulation was good (no bare wire exposed) and the rest of the oven looks OK.  This is actually the socket for the oven light so I checked the inside of the oven.  The glass lense that covers the light looks like it's in excellent shape, in fact, it looks new.  My guess is that there was an oven fire that traveled found it's way through the light socket and up the back of the oven.  The fact the glass covering the light in the oven looks new leads me to believe the previous owners found the problem and fixed it.

Instead of throwing the oven away I think I'll clean up the back of the oven.

Any suggestions on a good way to clean up zinc galvanized sheet metal?