Just listed my Late-2010 for sale on Craigslist. I'm out of town for the holiday and in a major city where Craigslist is actually useful (CL is no good for the small city I live in). However, listing my MBA on CL was a spur of the moment decision and my USB key with the OS is at home (three hours away). I bought the machine with Snow Leopard, have since upgraded to Lion, but understand that I cannot transfer that Lion license...so I'd like to reset to Snow Leopard. Is there a way to reset my machine to factory settings without the USB or should I pull my listing on CL?