Reusing Soil? Help

I have been doing so moderate indoor grows and was wanting to start reusing my soil. I started with good fox farms soils.
What is the best methods for killing the bad stuff and putting in the good stuff?
I know about cooking it at 250 degrees for 20 minutes? What should I mix in it to replentish the soil?

Sorry I know this has been posted before but i counldt find it.