Riversong, I know nothing about Bentonite clay detoxing, except that I'm not desperate enough these days to try drinking MUD. lol.... Although, it's probably not the dumbest thing I've ever thought of.
I've been suggesting ALA for a long time, and I don't remember the first place I heard of it. Probably a Pubmed reference, but it's a proven chelator, with a downside of creating yeast problems easily, and an upside of being available from any vitamin shop and being a LOT cheaper than DMPS, which would be my choice of chelators, based on my personal experiences with chelation. (but DMPS requires a prescription and is very expensive) Expect to spend 1-4 YEARS of gentle oral chelation.
Depending on how toxic you are, (I was EXTREMELY mercury toxic!) you will find that mercury comes out of you, a lot harder than it went in. My testing was all done by hair testing, and even then, had to interpreted because mercury likes to hide and screw other body processes up.
Now I understand it's possible to use a mercury porphyrin urine test, that even determines mass balance, although I don't know how that works, and I have no reason to try it at this point.
Neither do you, by the way. If you have Amalgam fillings, you have mercury, so save your money unless you have to prove toxicity to someone else.
I have some funny neurologist stories, but they'll have to wait for another time, because I'm late for dinner. :)