I an empathize with you since I run support lists in addition to helping out
with a few lately.

It takes a lot of work an dedication, but I and my subscribers appreciate the
work.

Set the list to be semi-moderated and set the Default-Options in the header to
REVIEW so that all new subscribers are set to REVIEW mode.  (this to catch the
spam and people that will try and unsub and resub to bypass moderation).

Set flamers to REVIEW, notify the list that flaming won't be tolerated and
people violating the rules will be placed under moderation.  Probably have to
spend a couple of days announcing how many members you've had to place under
review and re-iterate the mission/policies for the list to make a public
example and enforce your efforts.

Return messages to the originator with a copy of your list policies and don't
approve any you've caught via the review approval mechanism.

Within a couple of weeks things got back on track very nicely.  Justed helped
out a support list that was wildly out of control and it has vastly turned
around in little over a week.  All the hard-core discontents are gone and it is
starting to pick up subscribers, thrive and be supportive again.

If you desire help with technical details, give me a holler.

Randy
http://www.our-kids.org/