I use 190-proof straight ethyl alcohol (*) to remove rosin flux and clean PC boards.
Pour a little at a time into a working container and promptly close the original
bottle to minimize absorption of moisture from the air.
(Having experienced a chemically-induced anaphylactic-shock episode,
I'm careful about what I use for cleaners and lubricants.)
(*) Everclear is one brand-- a fifth (750 mL) lasts a long time.
And no, I never drink the stuff<g>.