You may not be able to get denatured alcohol at the hardware store
in California anymore but there are other ways to get it.  First, you
can buy it as stove fuel from Amazon and, as of August 24th (according
to a recently answered question), it will be shipped to California.

You can also buy 190 proof ethanol and pay tax on it.  It is used as
a solvent for many cannabis products.  It is not difficult to get but
you will pay about $100 a gallon.

You can also make your own.  I have a still that is capable of making
194 proof ethanol but of course it is illegal so I can neither make it
or suggest doing so if I want to be legal.  You can buy the still
legally but it is illegal to operate it.

Spencer Chase
Garberville, Calif.