in my traxxas s-maxx my glow plug snapped in half and the other half is still in the threads. how can i get it out?

i suppose you could take the hear off, and solder a allen wrench to the bottom side of the plug, and unscrew it.

Go to your local hardware store.  Ask for a screw extractor.   It's basically a backwards drill bit.   Should do the trick.  Jik's ^^^^ idea works to, just no soldering involved

I've been in this hobby for a long time and have never seen a broken glow plug...
Got any pics?

It should be easy to remove if all that is in the head are the threads if it's not cross threaded.