Not only is benzene a carcinogen, it is adsorbed through the skin and cause
cumulative damage to the bone marrow which is essential to the production of
your blood cells.  It is highly toxic. One exposure is unlikely to kill you,
but it will likely do hidden damage.  Benzene is one compound that chemists
try like hell to avoid using!
Acetone is much less toxic, but is highly flammable and volatile. 
It also dissolves lots of things so handle with great care!