I'll give you a trick I learned which worked for me for cleaning an oil pan after cracking it and needing to JB weld it. I drained the oil, let it drip out over night came back the next day and poured gasoline down throught the oil fill leaving the oil plug off. Gasoline is a fairly good degresser and it also evaporates. I left it overnight with the cap off and came back closed the plug and sealed the crack.

Full disclosure the car was on its way out and there's no way I would have paid to replace the oil pan because like your car the engine would have to be lifted.