[SOLVED] What is this brown stuff on my graphics card heat pipe

Solution
I’ve inspected the graphics card and I’ve noticed this brown stuff on the heat pipes, I’m wondering if it’s rust or if it’s just normal on older graphics cards.
That is oxidation.
Cooler there is nickel plated copper. When encountering high temperatures, nickel starts oxidizing and changes color slightly.
Welcome to the forums, newcomer!

I think you're referring to the brown stuff as soldering flux, which is what is used to mate the heatsink fins to the cooling heatpipe. Unless I've looked at something else entirely, you can shoot more images of the thing you're concerned about.