nadz, if you color over henna with any commercial die to lighten over henna (and this is anytime the henna is still in the hair, it can be a year after) you risk it turning all sorts of shades.

Henna takes the minerals from the ground that it grows in so no one is quite sure what is in it. If the soil it grows in is high in copper, and you use bleach on this henna all your hair will turn green.

Beer rinses are for shine, but I wouldnt recommend putting it on seriously damaged hair (vodka either) as it has a high alcohol content, which will further stress your hair. _____________________________________________________
"Diplomacy is the art of saying 'Nice doggie' until you can find a rock - Will Rogers"