Sterilizing fish tank

[Mii]

So a betta in my 10 gallon got dropsy, and I was wondering what I should do to sterilize the tank before I put anything in it. I have rocks and wood that need to be sterilized too, and sand substrate. Also, how do I sterilize plants and nerite snails? Note that I have multiple tanks, so I can move the plants and snails to use harsher treatments on the tank itself. But also want a way to make sure I sterilize the plants and snails well to make sure they're safe.