(Sorry, not an engineer or student, just looking for the most metallurgically relevant stack.)

Recently I was in someone's office and, while playing with their paper clips, it occurred to me that copper is kind of a precious material for humble paper clips ... one look at the box, they're merely copper plated. But why even do that though?

Why not just leave them bare steel or aluminium or whatever they are made of (which, curiously, the box doesn't say)?


  • $\begingroup$ A benefit is that they leave green marks on the paper if they get wet over time. $\endgroup$
    – Solar Mike
    Commented Jul 1, 2020 at 6:55
  • $\begingroup$ @SolarMike this is what's called green washing, yes? ^_^ $\endgroup$
    – KlaymenDK
    Commented Jul 1, 2020 at 6:56
  • 1
    $\begingroup$ Perhaps it's just because copper has a nice colour? $\endgroup$ Commented Jul 1, 2020 at 8:33
  • $\begingroup$ Yep. Aesthetics, "classy, expensive" looks. $\endgroup$
    – SF.
    Commented Jul 1, 2020 at 14:22
  • $\begingroup$ When your four-year-old sticks one in an outlet, the breaker will trip really fast :( $\endgroup$
    – Phil Sweet
    Commented Jul 1, 2020 at 19:30

1 Answer 1


It makes them not rust in humid conditions while holding papers together. The required amount of copper coating on the clip is extremely small.


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