Steriliseing soil

I tend to buy compost for seed sowing. But if I didn't want to for any reason, I would get some soil that has never grown anything but grass or weeds and keep it warm and light somewhere over winter to try and get as many weed seeds to germinate as possible. A good place to get some soil could be mole hills if you can. I needed some soil to help level off a bit of ground recently and got a wheelbarrow of soil from the mole hills on our lawn.