I use Pectasol Chelation Complex (hideously expensive even at iherb--nice if you have a friend with a, ND, DO, or even massage lisence to buy
it closer to wholesale for you.) It apparently pulls out metals well on its own; it contains alginates as well which allegedly allows you to
swallow less pectin than you normally would have to with pectin alone. (This from the guy who makes it, so grain-of-salt possibly needed.)
NOW Foods Modified Citrus Pectin (MCP) features a patented, low molecular weight citrus pectin that can pass through the intestinal barrier so it can work systemically. MCP can bind to and facilitate excretion of low levels of heavy metals that commonly come from mild environmental exposure. A recent study indicates that modified citrus pectin promotes healthy urinary excretion of common, mild environmental exposures of heavy metals such as mercury, arsenic, cadmium, lead and tin without altering excretion of other nutritional minerals, including calcium, magnesium, iron, copper and selenium. In addition, MCP has been shown to support healthy cellular growth and reproduction.