the cleanup tool doesn´t remodel your object by changing tris into quads. it shows you nonmanifold (which I benefit the most from) komponents as well as nonplanar faces and things like that.

if you want to change tris into quads you have to model it yourself like Eelco mentioned. there is a tool called mjPolyTool which creates edgeloops? but I have not used it yet, so I can´t really tell what it does exactly.