Cleaning sheet copper

I bought a home that has a two sided, or open, fireplace with copper canopies. These are made of sheet copper, with raised seams. The measurements are 5' X 10', on each side. The previous owner tried to clean one side with a liquid cleaner, and it had very bad results.

What can I do to remove the film that was left behind, and restore a presentable finish.

I have tried Brasso ⇦ on eBay or Amazon [affil link] , which works well, is very messy, and will take to long on this size of project, and will have to be a ongoing chore forever. Also 00 steel wool ⇦ on eBay or Amazon [affil link] , that resulted in the same results, very slow, it will work, but with the size of the canopies, it's going to take a long time. I'm considering more aggressive abrasives, but am reluctant to use them, although if I can obtain a constant duller finish, I would be satisfied.

Your expertise is welcomed,

Try this non abrasive approach. Clean the surface with Soapy water...let completely dry for a few hours Take a fresh lemon.... cut in half...press the cut end on the surface and view the results.

I've made a solution of salt dissolved in regular house vinegar ⇦in bulk on eBay or Amazon [affil link] and a cup and a half of salt dissolved would be an adequate volume for residential use. A soft mop for application will help agitate the surface without scratching.

RINSE THOROUGHLY AND COMPLETELY WITH WATER ALL SURFACES APPLIED.