You don't. It's only designed to kill running apps.
I downloaded and played with a cache cleaner, and aside from annoying adverts (it's a free version) it worked as advertised. I uninstalled it yesterday tho, as I saw no benefits from using it. Oh well.
Following Dan's instructions won't brick your telephone.
Not following exactly can have bad results.
In frustration, a friend's wife last week 'reset' her phone following directions she found online. It worked - but it cleared all her contacts, text messages, etc. Not what she wanted or expected to happen.
