Personally, I doubt vinegar will restore the hood. The best I have found is a powder called stainless steel magic... and believe me, it does require a LOT of elbow grease to make the transition from clean to shiny! But I have restored pans to like-new after DH burnt beans into a solid inch of charcoal on top of grey and that funny discolor that SS gets when it's been overheated. Lots and lots of elbow grease; is the BBQ really worth it? any chance you have insurance to cover the mishap? because it really sounds like replacement is needed more than just cleaning up.

I suspect the black backside and probably the brown front are mostly soot from the over-smoked duck; consider them grease and yucky-stuff, and clean the top layers off with household ammonia and paper towels before trying powders or other stuff.

Im sure I saw Johen Eakes DIY personality recommend ketchup for polishing copper. Would this be because of the vinegar content or the acid in the tomato? I tried it on my pan and didnt like the result, seemed blotchy because i let it sit on.

The acidity of ketchup does act as a cleaner on copper. Personally, I think the results too undependable. If you want an effective home-made substance, take a small bowl and put a couple tablespoons of salt in it; add just enough lemon juice to make a thin paste and scrub with that. Rinse well. Remember that air oxidizes copper -making it turn greenish or brownish- and the copper will re-tarnish rapidly. If the copper or brass is decorative, a lacquer finish will protect the metal; if the copper is on a pan or similar food item, then you might as well accept that frequent polishing will be a regular part of the cleaning process. I love copper for cooking, but I decided a long time ago that it wasn't worth the trouble of keeping pretty -- I now buy copper only if it is covered with stainless steel.

I tried a bunch of things but I guess the window cleaner foam with this plastic kind of scouring pad worked to about 85% completion. Someone recomended a pumice stone cleaner with pam spray, available at bbq section of home depot. I tried it on a back corner combined with the foam cleaner but saw some scratching.

Stainless metal properties could have changed after overheating. Keep in mind these home fixes and best guesses, like scouring salt and lemon paste. If you scratch it with any metal products like scouring pads it will rust later much faster. The tiny metal fibers will be left to rust into the stainless. I would stick to the liquids and pay the money for actual stainless cleaners made for a barbecue. The stainless paste used on fridges is more like a wax and would burn when heating up on the Bbq. I was a welder and we had stainless steel brushes for cleaning the metal, if you used a normal wire brush you could see the rust scratches withing two weeks. I have managed with very hot soapy water and rub with a lint free soft cloth, then another damp cloth to polish dry. That gets the grease, but the liquid polish would make it pretty...but that won't last very long.