I don't like the kerosene idea. Could damage bearings.
SNIP
I run a quart of kerosene for 10 min's at idle right before I shut off the engine and drain the oil... works really well to clean out the varnish..
On a 3.9 dodge V6 after about 10 oil changes with kerosene the oil started coming out nearly clean.. I had the engine out to change the rear main seal and it was spotless inside.. pulled a rod bearing apart from not getting an oil change for a unknown amount of time before I got the truck it was ok...
First oil change it came out like tar..
