The cabbage one is new to me, but the other has crossed my ears before.
In days of yore, it was customary to cook cabbage and other greens by
boiling in water with cooking soda for ages, until the leaves were
reduced to a nasty green pulp of no nutritious value whatever and
tasting somewhat putrid - but still nicely bright green, thanks to the
soda. So you wouldn't even think of cooking it again (although the
school dinners service might keep it in an aluminium container for hours
and then re-heat it before threatening the kids with dire consequences
for not eating it all up).
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-- ^^^^^^^^^^
-- Whiskers
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