Toaster oven? No. Heat treat oven? Yes. The hardened parts need to get to about 1500 F and be held there for about 1 hour per inch of thickness and then cooled slowly.
If you can build a decent size bonfire, you can likely get the pieces hot enough. Let the fire burn out and cool in the ashes overnight and they should be annealed. Or maybe find a buddy with a forge?
Craig