On 6/17/2019 10:48 AM, Oren wrote:
....

Might try soaking with liquid wrench over several days and tap with a
rawhide or nylon mallet -- see if it breaks loose. Soak the screw also
and try again. YMMV

Vinegar probably do more good against the hard water deposits...or,
never tried it for this, but the cola soda soak might be good...there is
the commercial CLR for Calcium-Lime-Rust but I've had little luck with
it. Lime Away has some hyrdrochloric acid.

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