From a chemically safe standpoint, denatured alchol is best! Plus, it evaporates without any residue, and will not interfer with any type of lubricant used on the lens. (Going back to my OTHER hobby here—woodworking) A SMALL dose of WD40 might break loose the jamup, but I'd let it work for 12-24 hours before I tried anything else. Works great to bust the rust, too! Just my 2 cents worth!
To photograph is to hold one’s breath, when all
faculties converge to capture fleeting reality.