iPrint appliance

I have a pair of old external renderers that have stopped working. On
the renderer side, I can't get them to unregister-- they report as
being not registered with the appliance. At the appliance, the
renderers are still shown as present. One is in "configuring" state,
the other shows inactive, and neither one can be deleted. Trying to
delete the "configuring" gets a result back that is has been
sucessfully deleted, but it is still showing on the appliance. Is
there a way to manually clear these on the appliance-- delete them
from the appropriate conf file? If so, which?