Just occured to me that I've been carrying a small fire steel on my keychain for about a year now. I remember leaving the heat shrink tubing off on purpose, to see what would happen. So far, it looks just about like it did a year ago. I use it occasionally, either to play with it or (usually) to start the fire when I'm grilling.

This is only a single data point, and my pocket is probably an ideal environment (never wet, hardly ever humid, since I'm only ever at work or home or some other air conditioned building). I'm also assuming that any corrosion would be at noticeable.

Anyone else carry one this way?

Note that this is probably a much different situation than storing a fire steel long term in a container of some sort.