Cleaning old unused hydraulic lifters

I put my 360 together in the 1980’s with Mopar Performance cam, lifters and spring package. The engine sat on a stand without ever being started. I have disassembled it for cleaning and found some of the lifters stuck. They have been now soaking in parts cleaner for several weeks. Haven’t checked to see the effect yet but wonder if I did buy a new set. With all the comments I see about current quality I wonder if I’m better off continuing to try and clean the MP ones from yesteryear. Can they be disassembled? What are your opinions?