How to factory reset CyanogenMod? We bought a used smartphone (samsung galaxy ace), and was suprised that it had a version name: 

cm7-democracy final edition 2012 (2.3.7 android)


We wanted to reset it in the "Backup / reset" menu in the Settings.. but it didn't allowed us to do it.. no plus menu came up when we pressed the "reset to factory defaults"

Question: how can I reset it to factory default? (with or without leaving the CM on the phone!) - we just only want to wipe the personal data from the phone, as it is a usual thing to do when we would only have a stock android on it.
You can go to the ClockWorkMod Recovery by pressing VolumeUp+Power+home button (For devices that have physical home buttons. Yours does!) In that you have the option to do factory reset/wipe data. Also don;t forget to wipe dalvik cache. That way your phone will reset to CyanogenMod factory default. However if you want to restore to Samsung Factory default you have to download the original firmware and flash it using Odin or any other software. Detailed guides can be found online