Here's one that shows it real well.
Attachment 174945
Printable View
Here's one that shows it real well.
Attachment 174945
Max, thanks for the photo. That is an apt display of the line in question. I'm lucky mine don't have that. I took your initial suggestion and used a wee bit of Maas compound to remove what miniscule staining there was on the blades and they shined in a few moments.
Attachment 175003Attachment 175004Attachment 175005
here are some examples also on a Joseph Rogers I have in the mail
showing it is just a corrosion area where the blade contacts the scales could be deep but I hope not