Black Spots on Ribs

[Stockmanreef]

I just got my RV-14 wing kit and started working on deburring the ribs. I notices that several of the ribs have black spots on the surface. THey are irregularly shaped and maybe 1/4" in overall size. The surface is not smooth where the black is. It is difficult to say whether the black stuff is causing the surface roughness.

Is this normal? Is it a type of corrosion?

I also found that several of the ribs have relatively deep scratches on them. I am pretty sure that I did not put them there. I guess I just have to buff those out.

Thanks
Ken

[Av8torTom]

Nothing at all like that on any of the parts of my 9A.
Take a pic and send to Vans.