Going back to snow leopard. How do I delete the Lion Mac OS X Install Image? I have a one generation old MacBook Air. I upgraded to Lion when it came out. Now I wish to go back to Snow Leopard. I booted from the thumb drive installer for Snow Leopard. There is a Lion installer image that I can't delete. Disk Utility greys out for that partition. It's not the end of the world, but I would like to get that 5 gigs back.

Any help would be appreciated.
When booted from the Snow Leopard install drive, you should be able to create a new partition from the partition tab.