Use a Maroon ScotchBrite Pad with WD40, the WD40 has fish
oil in it. Try to follow the original grain pattern direction in as long a strokes as you can, wipe off any excess WD40 when you are done, do not remove all of the WD40 as it helps to protect it and will help it look more original as time goes on. You can use 180 grit Sandpaper to get out any deep scratches, then go back over it with the Scotchbrite Pad with WD40. You may want to fold your Scotchbrite in half or use a sanding sponge behind it or a block depending on what you are doing. This will get you as close as you can get to the original finish, but not exactly, as time goes on they will look more original. I was told there is no way to restore the panels to exactly like original. I was also told this is way to do it by Renowned Cobra Restorer Dave Wagner. I actually just did the Engine Compartment Panels in my early Kirkham and they turned out great, but I will tell you it takes sometime to getting the pattern right especially on the long runs. Hope this helps.