I started a few seedlings indoors and I already have a house full of those nasty fruit-fly/gnat sort of bugs that can often be living in cheap potting soil. So, I remembered that you can sterilize it by baking it but I don't remember the details. Does anyone know how hot you should bake it for and for how long? Has anyone ever done it? Does anyone have any other bits of advice for getting rid of the gnats? Thanks!