How to clean your QT tank?

I've been pretty lucky to not have to deal with parasites and fungus cases in new fish very often but just recently I got a fish and noticed her tail fin was a little jacked up looking so I put her and the other fish i got along with her in my QT as I always do with new fish. I thought it was probably just a bite out of her tail but after a couple days it ended up being fin rot.

So my question is, that once the sick fish is out of the aquarium(whether it be death, returned to store or healed) how do you sanitize the tank so that incoming fish don't get what the last ill fish had

I think chlorine bleach is the best way to go. It pretty reliably dispatches any pathogens, and between thorough rinsing and dechlorinator you can neutralize the chemicals.

I agree with Fyurae, good answer!!!!!!