Reply by msinc

I like PB blaster as an initial clean and degrease…it penetrates old hard grease pretty fast. It will run right down into the thread and start to work immediately. It also helps to loosen up any rust that may be present too. Usually, in pretty quick order it will at least get the thing freed up and spinning easier so you can go to some sort of solvent to finish cleaning it up.
Molybdenum disulfide grease {anti seize} is probably about the best hi-pressure grease out there.