I recently purchased some Lodge preseasoned cast iron and read some advice that suggested I re-season it myself. I coated it inside and out with some grapeseed oil (high heat point, per the recommendation) and stuck it upside down into my hot (500ish) oven for nearly an hour. By that time, my apartment had completely filled with fumes and the smell was horrible, so I decided to take it out. I can't tell whether I did something wrong -- is this supposed to happen?? I now have a very dark pan, though the black covering doesn't appear to be uniform.