[KevinW]

If you want a Kirkham-like mirror finish, there is no alternative to rubbing down through al the wet'n'dry grades and then mopping several times with metal polish - it will take several hours to complete for a good job.

But if you just want it to look a little smarter then a few goes with the above products will get rid of the dull look and it will have a shinier lustre.

I dont know the shape of a SPF firewall, but im guessing it wouldnt be that hard to cut one out of .5mm or 0.7mm stainless if you want a long-lasting shiny finish.