One suggestion, if it is not too obvious, is that maybe individuals who can't take DMSA should focus much more heavily on sweating, e.g., saunas, sunbathing, or hot baths. Andy mentions yarrow, which I take and like, but I know there are some other herbs to help sweating. Magnesium is necessary as well. And if you do sweat a lot, you can deplete potassium pretty quickly, which is why I always eat a lot of Watermelon in the summer.
And of course, paying a lot of attention in keeping the gastrointestinal tract, liver, and kidneys clear.