I keep my spikes in a little bottle for Ferrous Sulfate. I use to have an iron deficiency, which apparently I got over the summer by walking around barefoot. I was told that I pounded the iron out of the bones in my feet. It wasn't difficult to breathe, but breathing wasn't as worth it. The amount of oxygen that you take in on each breath isn't as much. It makes you a lethargic runner.
I had fun with it though, and got over it quickly. You can get iron supplements in just regular vitamins. We called my ferritin levels Ferrets, and when I didn't need the pills anymore I used the bottle to hold my track spike spikes (it makes sense because iron).