Beef bones / bone marrow

[chaan]

Recently I have bought grassfed bone marrow/bones from beef for the first time. After I made my first broth I saw that a few of those bones were partially coloured grey. Not only at the outside, but also partially from the inside. Because I want to re-use the bones for making broth I want to know if these grey parts could be harmful or not. Those parts don't look very appatizing.

[dagnytaggart]

I have noticed the same thing when I make broth and I believe it is normal. There is often a grey coating of surface scrum around the top edge too.