I just received a new old forging of a 6/8 Le Grelot. After a fantastic first shave with this beauty - little grey spots have appeared on the blade. They don't look like rust - but cause me some concern. I rinsed lightly towelled, towel-stropped and finally briefly leather stropped following the shave. This also recently happened to another NOS Solingen Silver Steel razor I picked up. Both blades came covered in oil and were pristine prior to the first shave. I cleaned both with alcohol, soap and water prior to the shave. Is there something with historical carbon steel? Any ideas on how to polish / clean these spots? Any idea how to avoid them?