Guessing the oil is staying in there for a very long time. You could wash it out with a solvent, I wouldn't. The other way is to start the engine.

This doesn't help the situation, if you have a borescope and see crosshatch without any corrosion it will probably be good. These motors have a VERY robust lower half.

Putting compressed air in the cylinders for a few minutes each cylinder might blow the oil out of the rings.

Good luck!!!

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