Andy Cutler, PhD Chemistry, detox consultant and author said MCP is not a true chelator of heavy metals. His definition of chelator included the existence of two sulfur-hydrogen (thiol) groups to better grab onto the HM atom.
I tried it prior to starting Cutler protocol detox. I did not have any significant side effects--unlike the many unpleasant reports from people who used cilantro, "green juices" etc.
I suggest you stick to the things that have more Science supporting their use and long history. That allows people and their med pros to come up with a decent detox protocol.
If you still have Amalgam fillings--50% mercury--selenium plus other antioxidants--vitamin C, E, etc might be a safer route than the "green juices".