Originally Posted by
Skyangel
For the brown gunk on the insides I usually use kerosene on an old toothbrush, then follow with Tri-Flow.
Be careful using this sequence... Kerosene is a great oil breakdown chemical, but for the same reason, if you do not get ALL of it out of the little nooks and crannies and between moving parts, you will be breaking down your new oil soon...
I only use the harsh oil cutter methods with parts that I am removing, so that I can be sure to clean it all.