How to flush blue devil out of the cooling system

The only way I know of to remove sodium silicate is to use very hot water to dissolve it and flush it out. Clearing it out of heads that are off should be easy, just toss them in a large container, fill it with hot water and let it dissolve. Then use something like a parts washer pump to flush the passages with clean water. Doing the block is a bit harder. I would probably do the heads, use a brush to get as much of the stuff out of the passages you can, then put it all together, leave out the thermostat, and fill it with straight water, run it until it gets hot and then drain the water, do that a couple times and maybe add some radiator flush as well. That should remove most of it.

Please keep us informed. I would be sure to keep water in the heater core if at all possible. Maybe connect a couple lines, fill them and plug them. That way the crystals won't form and block the flow.