If you have purchased something called "shellac thinner" and it is
now unavailable then you simply need to educate yourself.  Thinner
for shellac is alcohol.  There should be no toluene anywhere near it.
Toluene is lacquer thinner, also called tulio by some.

The best thinner/cleaner is methanol, also known as wood alcohol.
It is no more flammable than a dry martini but don't drink it.

Alcohol that is watered down and nasty smelling is called denatured
alcohol.  The odorant is added to make sure you don't drink it as it
will destroy your optic nerve in about 15 minutes and give you lifelong
blindness.

Methanol [methyl alcohol] is close in chemistry to ethanol [ethyl
alcohol] which is added to gasoline for fuel efficiency.  I don't know
how it would work as shellac thinner, though.  Perhaps some chemist in
this group can tell us more.

On searching the California codes I could only find reference to
methanol as a gasoline additive, so with more searching you may find
it by itself.

Try shopping for methanol for shellac and let us know if that is
banned.  It shouldn't be.

Doug L. Bullock
http://thepianoworld.com/ 

 [ See also https://en.wikipedia.org/wiki/Methanol  and
 [ https://en.wikipedia.org/wiki/Denatured_alcohol  -- Robbie