Heavy metals will bind to charcoal through a process called cation exchange. For this process to take place, the charcoal must make physical contact with the heavy metals.
Unless they are in the digestive tract, this will not occur, so we must mobilize the mercury so that the liver escorts it out through a bile dump. The body needs a powerful antioxidant to release the toxins (via cytochrome enzymes), the energy to mobilize the mercury, and a binder in the digestive tract so that the mercury is not reabsorbed.
We sell a glutathione product that will help with the release, and our charcoal will help with the binding, but for the mobilization, we would recommend using a quality cilantro oil in combination with R-lipoic acid, but please be advise we are not doctors.
Please check with your client's medical professional before starting any heavy metal chelation protocol (unless you are the client's medical professional, then use your best judgement in accordance with your experience and education).