How'd they heat leftovers before microwaves?

I was just looking in the fridge for some dinner, and found some leftover Chinese (food) inside. "Hmm, how will I heat this?" (I actually do have a microwave, but it's in the basement and it's an older, bulky one, so I haven't moved it up to the kitchen yet. I don't even know if it works.)

I thought, well, I could heat it up on the stovetop; but I really didn't want to stand there over it; then I got an idea: put it in the oven! Since the food was, unhelpfully, in microwave-safe plastic, I transferred it to metal pots, set the oven on 290, figuring it'll heat up slowly (meaning if I get distracted blogging, it won't turn to charcoal).

Then, just as I was congratulating myself on my idea, I sheepishly remembered: "oh yeah. This is how mom used to do it. All the time."

Thanks mom!