Coleman stove lantern mantles contain thorium, too. When the lamp is first lit, the silk burns off, and a thorium oxide skeleton remains, which becomes incandescent in the gas flame.
They don't anymore, although I understand that you can still get cheap chinese mantles that incorporate the thorium. It seems like thorium lamp mantles belong to a growing group including things like incandescent lightbulbs, CRTs, pseudoephedrine, robutussin, and other things that work too well and must be villified or banned.