Product review (4 stars): DIY Disposer fix
This product makes fixing garbage disposals quick and easy for anyone. You don't necessarily need to buy this if you have the right size alan wrench and in a pinch I was once able to use the back of a screw driver tip.

Basically you need this product because it fits into garbage key hole, underneath. Once in place spinning the key will dislodge debris. Sometimes you also need to press the red reset button under the disposer. Always run lots of hot water when running your disposer to help break down debris. If something is still rattling around inside your disposer and you are super brave, with the disposer off, stick your hand in there and pull it out. If you can't pull it out call a plumber! Goodluck