Not really sure I trust that last item - it sounded interesting so I
"This may sound strange today, but back then, the pain of the houses
contained limestone. Limestone is a powerful disinfectant, and not many
others were widely used at that time. Thus, Greek citizens whitewashed
their homes to disinfect them and reduce the spread of cholera."
Apart from pain instead of paint...
Limestone is not a powerful disinfectant.
If you bake limestone (calcium carbonate) you get calcium oxide, AKA
quicklime. Mix that with water and you get a calcium hydroxide slurry,
AkA limewash, and that's the disinfectant.
"The blue used in the islands' houses in the blue Aegean sea was made
from a mixture of limestone and a cleaning product called 'indigo.' The
indigo was a type of blue talc that most of the islanders easily had at
home. Therefore, blue was a very easy color to make."
Indigo was never a cleaning product AFAIK. I'd assumed the blue was
lapis lazuli, which comes from Afghanistan and cost an arm and a leg in
ancient times. But I assume this guy knows something and
tells me that most true indigo also comes from the East. Not likely to
be cheap when it's gone overland by camel train for a few thousand
miles. It also tells me you can get blue from murex shells - where one
of the shades is called royal blue. That doesn't sound cheap either.
Almost identical text appears in other older articles, except they say
the blue was a cleaner called loulaki. Which is also a Greek name. Too
hard for me to look further.