In Mast Halyard Swivels maintenance

closereach <no_reply@...>

I've noticed on my Sharki that furling and unfurling (nonelectric)
both my mizzen and main sails takes a bit more effort. I've dropped
both sails to inspect the hardware. The Amel halyard swivels on both
don't turn as easily as before. Any suggestions on how to make them
rotate more freely? Special lubrication?