On App exit || App logout(firebase) , how do I destroy scope(for a lack of a better term) in ionic 2?

[eangeles92]

In my ionic 1 app I destroy scope by iterating through it and that was my extent of my clean up when a user is no longer logged in. Now that ionic 2 is here how do I perform that same type of clean up? local instances of variables in memory, listeners, watchers etc. thanks