During the Prohibition years in the USA, where from 1920 to 1933 all
alcohol [consumption] was banned, the situation is a bit complicated.

Grandparents on both sides of my family had experience with illegal
spirits.  In my home of Cleveland, Ohio, they'd wait for Lake Erie
to freeze over and drive to Canada, fill the trunk with whiskey, and
drive back again (with the car doors open for a fast escape in case
the ice broke.)

Industrial alcohol was still legal during Prohibition, and these were
denatured alcohol, which is grain alcohol, or ethanol, that has been
mixed with formaldehyde to make it non-drinkable. (Attempts were made
by organized crime to extract the formaldehyde and thus render the
stuff drinkable, but with no known success.)

Methanol, or wood alcohol, is sold for shellac thinner and other
industrial purposes, and it's as poisonous a product as you can find
then or now.

And then there is isopropyl alcohol, which is the 'rubbing alcohol,'
with or without oil of wintergreen mixed in, that is sold widely in
drug departments in concentrations of 50%, 70%, and 91%.  I use this
last for getting glue residue, especially epoxy, off my hands because
I'm clumsy.

Wouldn't this isopropyl alcohol make an efficient shellac thinner?
I've accidentally removed a bit of the shellac finish from our house's
interior trim with the stuff when I was careless with it.  In any
event, it's available in quarts.

Mark Kinsler