Staedtler do manufacture a very nice product for permanent marking, actually they make a few, but their Lumocolor Permanent marker stands out from almost all others.

It doesn't dry up if left uncapped!

Only because we have a fair few house guests in our place, did I learn of the existence of a "Sharpie" pen. I heard of them on APUG last year, but didn't know what they were, so I asked a house guest, she promptly pulled one out of her backpack to show me.

Mick.