I'm on a mission to find a system for marking vegetables in our garden that will last through a Northwestern US summer. Plastic stakes & black Sharpie don't do the trick -- by this time (mid-summer) the "permanent" Sharpie has faded and is pretty much unreadable.
Ideally the markers would be relatively easy to clean and reuse as we often adjust the type and quantity of vegetables that we grow each year -- so I don't think the embossed copper ones would work (because I imagine that they would be hard to change).
I've seen some folks suggest a "wax pencil" on galvanized metal markers, but I'm not sure if any wax pencil would work or if there is something particular to look for.
What works for you?