This ammonia smell is not uncommon. I've also experienced it myself when my amalgams were still in (but not anymore).

I would increase water intake if possible and make sure sugar (hydrogen) intake is low. Changing the pH of the body towards alkaline may also help. You can do this with cucumbers.

Here is an informative link explaining the chemical process:

http://www.bodybuilding.com/fun/ammonia.htm


As far as sharing mercury toxicity is concerend: Yes, I believe this is a very real issue. I would take simple precautions like washing sheets and towels often, etc.