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That looks like swarf. Scrape it off with a chisel and spray on Oven cleaner, scrape again and wash in soapy dish water with a Scotch Brite pad, then soak in Simple Green or any degreaser and water...

Try tapping down on the end of the paddle with a small hammer, on either end to see if it is glued to the paddle or just mortised in. If mortised, it will come loose, old swarf only holding it in....