I have noticed the chatter of the good and evils of Whiteout as an
antiflux. I understand why you would pefer it to the yellow ocher
liquid, which runs and boils everywhere that you don’t want it.
I recently tried something new. Any of you have the brown or yellow
pencils for marking flasks and investment when casting? These I
believe are ocher in a grease base. I simply coat the piece with my
boric acid/alcohol mix and let it dry, then warm the piece and apply
the pencil where needed. It doesn’t go everywhere when used like the
liquid, and as far as I know doesn’t have bad fumes. Perhaps someone
with more resources/time could check on what the binder is, but it is
meant for burning in the kiln. It has always cleaned up well in the
ultrasonic.
Give it a try? Let me know how it works for you!
Allan in Idaho