I found that Steel Wool cleans old Blast Deflector Plates very nicely. Scrub under running water , perhaps some soap. Afterwards, add thin layer of 3 in 1 oil to prevent further oxidation. You’ll be amazed at the difference ! Pics say all, Before and after…
Both pics are the same one…..

Attached Thumbnails

   

__________________
ENGINE COSTS ARE " OUT OF SIGHT " .....