Methyl (and other stuff) is used to denature or make ethanol poisonous.
<u>
http://www.newton.dep.anl.gov/askasci/chem00/chem00102.htm</u>
"Question - what is the difference between denatured alcohol and
rubbing alcohol?
------------------------------------------------
Denatured alcohol is ethanol to which poisonous and foul-tasting chamicals
have been added to make it unfit for drinking. There is more than one
recipe for denaturing alcohol; some add methanol or isopropanol, some
gasoline, and so on.
Rubbing alcohol is an alcohol intended to be rubbed on the skin. Frequently
70% iso-propyl alcohol / 30% water is used; sometimes ethanol with added
iso-propyl alcohol is used. You don't want to use denatured alcohol that is
made with anything that shouldn't be placed on the skin, such as gasoline!
So, some, but not all, kinds of denatured alcohol can be used as rubbing
alcohol. Rubbing alcohol may also not contain any ethanol at all, which
would disqualify it from being "denatured". So, some but not all kinds of
rubbing alcohol are denatured alcohol, and some but not all kinds of
denatured alcohol can be rubbing alcohol.
Richard E. Barrans Jr., Ph.D.
Assistant Director
PG Research Foundation, Darien, Illinois"