Nasty head, what to do?

In effort to get my motor running as best as can be; I popped off the valve cover to replace the gasket and found the head to be a disgusting mess of crud. Seems the prior owner ran the motor, without thermostat or proper oil changes, much longer than I thought. Any ideas on cleaning this mess short of taking the head off for a cleaning and valve job? I'm sure the pan is full of crap as well.

Leave it be for now...if you go picking at it...there is a good chance you could get enough chunks in the pan to plug up the oil pickup screen...