What's the reason massage of the lymph system removes toxins?

Lymph: Lymphedema is a collection of protein debris. The lymph channels may be small or the numbers low. Proximal massage can help the channels "unplug" and allow return of the lymph up to the chest area where it is gotten rid of by the body. The lymph protein is considered breakdown products ie toxins.

Lymphatic Massage: Lymphatic massage is a very gentle form of massage. The lymphatic system is made up of very tiny vessels that remove toxins from an area. Lymphatic massage involves bringing lymph toward the nodes that they empty into and encouraging lymphatic movement toward the heart. It helps to remove metabolic waste products and toxins.