How To Clear Phone Without Losing Flash

Hello, i have a droid 3 that has been flashed to cricket. i am going to sell my phone today and need to remove all my information off of it. I know if i do a factory reset it will mess up the flash and im trying to keep the flash on the phone. Is there a way i can remove all my contacts, personal info, clear passwords and everything without doing it all one by one?

If you are rooted go into clockwork recovery and just clear the data and phone info. I know that will clear the phone,but I never flashed a phone to another carrier so not 100%

Where is the clockwork recovery located? And are you saying if i do that it may delete the flash?