Here's a few more pieces of information on shellac that conflict a bit with
previous responses.

There are two different issues that come up with benzene content in ethanol
(grain alcohol) and the subject of denaturants.  In just a good pure water
mash of grains that is distilled to separate off the ethanol, some rules of
chemistry define that the best distillation will yield 95% ethanol and 5%
water.  That is essentially the 95% alcohol = 190 proof "moonshine".  If
diluted, you could drink it safely.  This would make a terrible solvent for
alcohol where you would like zero water.

For some chemistry applications, one would want to buy 99.99% alcohol.  To
distill alcohol/water mixtures to get nearly pure alcohol, benzene is added
to the mix.  It is then possible to distill off a mixture of 99.99+% alcohol
and less than 0.01% benzene with essentially no water.  This is not safe to
drink, although college students try it every year, and can cause blindness.
The benzene is indeed poisonous, but is not in a high enough concentration
to be a true denaturant.  If you care to, you can remove the benzene.  That
is why this alcohol usually comes with a liquor seal and heavy taxation.
The small amount of benzene is harmless when it evaporates as in shellac
finishing.  The most common denaturant to both make the alcohol poisonous
and very difficult to purify back to drinking alcohol is methanol = wood
alcohol.  Most borg-like stores sell ethanol denatured with methanol and
state on the can that methanol is included.  Most woodworkers use this
alcohol to dissolve shellac although the alcohol from Hock and others will
be guaranteed not to include water.

If you are going to brush shellac on medium to large surfaces and not just
tool handles, I happen to like Behkol from Behlens.  It includes anhydrous
ethanol and some isobutanol.  It smells very much like denatured alcohol and
goes on real smooooth.

When dissolving shellac flakes in alcohol, the more concentrated you make
it, the longer it will take to dissolve.  Heat helps and you might be
tempted to do this, but do not put the container on the stove or even in a
double boiler.  It can catch on fire or explode.  There is a similar
solution that works and is relatively safe, especially if you have an
electric stove or hotplate.

Try to dissolve the flakes in alcohol in a glass container (jar).  When not
stirring it, keep the jar capped.  Heat a small pot of water on the stove to
around boiling.  Remove the pot and put in on a safe surface away from the
stove.  Put the uncovered jar in the hot water and stir the contents.
Repeat as frequently as you have the patience for, removing the jar from the
water before reheating the water.  Make sure to keep the jar away from the
stove.

It might be a bit quicker to reduce the flakes to smaller sizes in a
perfectly clean coffee grinder borrowed from a neighbor, but this really
isn't necessary if you warm and stir as above.

Gary Laroff, who got his doctorate in chemistry doing research with
alcohols.