I own a replica claymore with a carbon steel blade. It is my first sword and I followed the instructions for blade preservation closely. Lately I have noticed some black spots on the blade. I can't feel them like you can sometimes feel rust and they arent very noticeable. It is like the blade simply changed color. They have been resitant so far to cleaning attempts I've tried. Is this the beginning of pitting and is there anything I can do to prevent or repair this?

Try using some Flitz to clean up the blade. If there is any pitting, you will not be able to fix that, but it should take off any surace corrosion. After that, wipe the knife down with a Tuff-Cloth, and give it an occassional wipe to maintain. Not the only method, but one to try.

May sound odd, but a # 2 pencil lead rubbed lightly will remove most small area spots. Then the flitz etc.
Mike