Never tried claydot, but cleaned a whole bunch if TiteWad and REX powder out of the trigger of a 391 when that was my main gun. Like timB99 said, with a breakopen gun, there is less to clean, whatever powder you use.
Try using a minimum load of Blue Dot in your pistols. Dirty as heck. Nobody would confuse Blue Dot for a cheap powder. Some powders like it a little higher on the pressure spectrum for clean, complete combustion.