On Apr 11, 9:38*am, Matt wrote:
I have a heat exchanger made up of stainless steel plates brazed
together with copper filler. *I have collected some crud inside the
exchanger that I can't for the life of me get out.

snip

Have you discussed the problem with the manufacturer's customer
service? Ask them if they have a cleaning service to offer. The device
is expensive enough to warrant such a service.

Joe