Selenium is an essential trace mineral and is absolutely essential when taking iodine, as they are both co-factors for one another. Whole food derived selenium has a world of benefits and is much preferred over other forms. It can also safely be taken in amounts greater than the "artificial" forms.
The metallic taste in your mouth you relate to coffee enemas may be the result of increased toxin removal made possible by the coffee enema. Coffee enemas cause the liver to produce more bile (which contains processed toxins) and moves bile out towards the small intestine for elimination. This frees up the liver to process more incoming toxic materials that have accumulated in the organs, tissues and bloodstream.
Why do you cringe when you think of Milk Thistle? Milk Thistle has been approved by the German E Commission as being effective at both protecting and regenerating the liver.