This is probably obvious to most, but be sure to power off your H2 before attempting to remove an extruder blob. I unfortunately missed doing this with a large blob that had unknowingly wrapped around the left thermistor wires; when I pulled the blob from the extruder, it caused a short which damaged the control board in the print head.
The heater was damaged and needed replacement either way, but switching the printer off would have avoided damaging more circuitry upstream.