I've googled the web and here's what I've found:

1. Andy Cutler says not to TOUCH ALA with amalgams in place:

http://onibasu.com/archives/am/208048.html
http://onibasu.com/archives/am/119971.html

Andy's recomendations of what to do before amalgam removal

http://onibasu.com/archives/am/907.html

Moriam's excellent index of Andy posts on various discusson boards:

http://home.earthlink.net/~moriam/ANDY_INDEX.html#dental

2. "Q: Do you use TD-DMPS with amalgams or do you remove them first? A: Get the mercury out of the body because removing amalgams can be very expensive. Just chelate the mercury and don’t remove the amalgams. If you do remove the amalgams, it is a good thing to get an IV-DMPS within 12 hours because the mercury floating around the body is so high, but you can chelate with the amalgams still in there. They will not disintegrate or fall apart."

From: http://www.defeatautismyesterday.com/Buttarnotes.htm

3. "Also a metal chelation group is telling me that my symptoms are definitely from chelating w/DMSA for 5 months while amalgams still in. But NP told me yesterday that�s a myth."

http://www.medhelp.org/posts/show/200838

4. This guy asked the same question in this "curezone" thread:

http://curezone.org/forums/fm.asp?i=36450#i