My wife was a good cook before we moved into our present home. Now when she bakes, the food gets overdone on the bottom before it gets brown on the top. However, the problem probably is that the door doesn't seal very well. This would mean that the oven would have to stay on longer to satisfy the thermostat, and that could cause the cooking problem. Examine the door gasket, and check to see if the spring is pulling the door closed tightly like it should.
Petroleum jelly is an incredibly useful concoction.
Many people use the stuff in the medicine chest. We also use it in the workshop. If you'd like a free list that we have put together of some of the many uses we've found in the shop and around the house, send us a self-addressed, stamped envelope here at the paper. If you've got some super uses for this stuff that we didn't includ e, send them to us so we can add them on. Those of general interest will be used in future columns.