Just looking at the question from a purely analytical perspective, all of the ovens that I have owned have the lowest setting at 200F. You would have to just heat the oven up to 200F, and then turn off the thermostat and put your tobacco in with the door open to try to keep the temperature below 170F. 170F is the magic number. If you leave your tobacco at this temperature for any length of time, you are altering flavor and cooking the tobacco. I would suggest that you just heat up an eye on the stove, turn it off, and set the open tin on it for a while. But, once again, you don't want it over 170F. If you can touch the eye, that might be a guide to temperature. If the eye gives you third degree burns, it's too hot. If it is merely second degree burns, then you are good. :
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I might recommend putting an open tin under a light bulb for a while. You would lessen the risk of cooking the tobacco.
Cooking it isn't terrible, but it does change the flavors some.