Properly cleared iphone

I am trying to clear my 3GS to sell. I cleared it through itunes but I'd like to clear it again. The problem is that I took the sim card out and it won't connect to itunes again so I can re-clear it.

Is there another way I can re-clear it without a sim card? It won't let me do it through the phone because it is not set up. I cut that sim card down to fit in my new phone.

Is it that important to clear it more than once?

 

Hmm. Thanks. I'm new to this so it's a bit scary. That doesn't jail break it does it?

 

Great! I'll give it a try. Thanks!