Sorry about the sniffing, I have a cold.
Every season when we change from winter to spring and fall to winter I like to flush my cooling system and block out with cleaner and replace the coolant.
This gets the junk that settles in the block that can cause hot spots around the cylinders and gets sediment out of the radiator and heater core making a more efficient cooling system and a better working heater.
This is how I go about it, including how to use RTV instead of a gasket for a nice clean looking mating area of the thermostat housing that never leaks or seeps like some gaskets.
You may also note that by introducing the water/air blasts into the thermostat opening the engine and radiator are flushed in reverse of normal coolant flow, as this helps to remove junk that settles around nooks and crannies where normal flow direction can deposit it.
Reverse direction flushing also removes particles from the radiator and heater core tubes instead of further embedding it into them.
Hope this helps.