9/2     Why does hairspray in a metal spray can pollute air, while the
        identical hairspray in a plastic spray bottle does not?  Thx.
        \_ the aerosol propellant in spray cans used to contain cfc's.
           i think most don't anymore tho. obviously, plastic spray
           bottles don't have a propellant, you need to pump manually.
           \_ I have heard that they start to use carbon dioxide for
              propellants now.