Pearl Wire Rings - these have, for the most part, gone through the pinkier spectrum of rusting but also, somewhere along the way, blue! Very unexpected. Must investigate.
Suspender Clasps and Hook - I love the emerging edges where you can see the vulnerable metal beneath. And below, a trio of rusty friends whom I found on my walk to and from work today. I like the idea of including found weather-worn items in our experiments and not solely items that we have set about to deliberately rust/affect.