I read something interesting that someone does routinely before starting seeds. Get the pots ready with whatever mix you're using, then pour boiling water on them all and wet them thoroughly. Let them cool of course before then planting your seeds, but I would think that would kill off any diseases or bug infestations in mixes, especially in older mixes. But even fresh store bought mixes can contain bugs if you read reviews. I've been keeping my mixes stored in old plastic coffee containers from the store, but even so they can be in the basement for years before I use them again.
