65 frame question

[SawyerBeavers]

So I just removed the bed on my truck and found this attached to the frame on both sides. I'm not sure what purpose they serve and was wondering if I should remove them or leave them alone?

Second question I had was about the coils, are they in pretty rough shape? Are they worth replacing and what will replacing them help with?

Last question, what would be the best way to clean up the frame? I was planning on just hosing it down and wire brushing it with some cleaner.

This is my first build so any advice or tips would help a lot!