Rombos marks in the chrome?

I've been working the chrome frames and I find these marks ... They were produced by a "dam"? What do they have?


Attachment 469338
Attachment 469339

It's aluminum, not chrome and probably due to fabrication to clamp the M8 or 10 inserts in the frame

cees

Aluminum that piece or the entire frame?
it looks in the picture is dirt

Your door frames are anodized alu, yes. The steel nut inserts are pressed in, the brown is dirt and some corrosion.

I cleaned them, but I did not take a picture of that area. With a brush and degreaser I look good! I found a small rust to which I had to apply deoxidizer and use due to the "steel wool" zone. If I return to disassemble the frame. I will add a picture although I do not see any interest in how it looks!
Thanks for your answers!!