Clenbuterol has two secondary effects that are beneficial to athletes and bodybuilders. The first is a strong anti-catabolic effect, which means clenbuterol decreases the rate at which protein is used up in the muscle cells, consequently causing hypertrophy of muscle cells (with proper training, of course). Clenbuterol accomplishes this by the stimulation of both type 2 and 3 beta-receptors. 3-beta receptors are more abundant in livestock than in humans. This explains the pronounced anabolic effects on livestock as opposed to humans.
Secondly, Clenbuterol has a wonderful thermogenic effect. This is the main reason that clenbuterol is included in nearly every cutting cycle in some form or fashion. This means that clenbuterol slightly raises the body temperature of the person taking it. When the body's temperature rises it burns fat more productively. When stacked clenbuterol with an LT-3 hormone such as Cytomel, the body turns into the fiery pits of hell and burns fat like a stripper scoops up dollar bills on a Friday night.
So if you were to keep a clean diet and hit the cardio, you can burn up the fat around your chest.