DOVO Favorit Cut Throat Razor Solingen Germany

I bought this in the late eighties or early nineties.  I used it once and after cutting half my face off I put it back in the box. I have just found it and I’m afraid it has suffered the consequences of not being cleaned properly when I stashed it away.  I am sure that there is a wrong way and a right way to clean it so I’ll leave it to the collector who buys it.  Please see photographs and description.  Will be sent post free 2nd class signed for within the U.K.