Would it be more effective to state “Remove from the body and heal the effects of heavy metals and all other substances present at toxic levels?”

This indeed would be superior and for the reasons you understood in putting the wording together in this fashion. As an outside agent instilled without human knowledge or awareness by interlopers desiring to cause harm who do not belong in the earth plane to begin with, the divine realm has full latitude to simply remove such substances even though it is the free will desire of the interlopers to do this, but someone must request it and this must come then from the human side, not from the divine realm side. So you can speak for one and all through the various means of the Protocol work to bring great benefits to humanity with respect to this menace. Once the mercury is removed, healing will be more straightforward and certain, and gains will be retained, so it will not simply be a back and forth with some healing being accomplished and then with further exposure to the mercury present, those gains will be lost and then the person back where they started. With this sequence of first removing the offending agent and then going to work to heal the damage, the benefits will likely be long-lasting and improving over time with repeated rounds of healing.