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Most all quality razors have brass or Bronze washers,some have boses moulded into the scales,JME

Actually most Quality razors have inner washers,nice job,scales look great.

Only if you can run it thru an ulrasonic cleaner.you have a 100 yrs of Dust, dirt, oils and shaving soap in that crack.
CA may work but all has to be perfecatlly clean.

No, use mineral oil,cheap at any drugstore.

Beautifull Ivory scales,warm water, some dish soap
some pipe cleaners as above, a toothbrush,just clean them, rub some mineral oil into them,would not worry about the crack as it is on the wedge...