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I used a few drops of Dawn dishwashing detergent in a couple cups of warm water, soaked a facecloth, wrang it good, and wiped and rubbed it right off. I dried the guitar with a cotton cloth and problem solved.
Late to the party and I'm glad to see you got your issue fixed. The only thing I can add is that I'd personally not use water on a cracked finish. An intact finish (like I assume your 330 is) is one thing, but if the finish is cracked naptha would be a better starting point to reduce the chance of swelling the wood.
And, the lesson of this story is....
An unsealed basement is no place for storage of musical instruments and amplifiers...or anything electronic....or much of anything of value.
Keep your fingers crossed that the moisture did not get inside the pickups---small chance that it did not---and caused corrosion there that will end up causing pickup failure.
+1 on the naptha/lighter fluid...for future reference.