I have one of these curious end-loading toasters from the 40's. The bread loads on the end and travels across the elements and falls out the other end on a ratchet style toothed belt powered from below. Not having been used for years it is gummed up. The grease is hard and not happy. The question is can I use something like DeOxit to soften the grease to loosen it or do I have to carve it out and start again?

Random unhelpful thoughts:
DeOxit seems like an awfully expensive solution.
I gather you are trying to free it up without taking it apart? I would be concerned with using anything that might leave a residue near food.

Maybe try scrubbing with a baking soda paste first? (I googled 'cleaning deep fryers ')