Well, hello there! So I recently came across this issue with my Google Nexus 4 and I am pretty sure it's a simple answer but I still want to double check before I screw this up. This is my first phone to actually root successfully, I am running an up to date version of purity rom, have a custom kernal to go with it,and on top of that I also have TWRP as my custom recovery. I recently bought the Nexus 5 and I want sell this one to one of my friends with the actual purity rom in the phone and dont know how to do a clean install without it having my personal data in it, should I factory data reset all the phone and reinstall the purity rom and gapps , or a friend of mine told me to just format the data and itll be fine. Like I said this is my first rooted phone and Im basically new to this. My friend wants the phone rooted with purity and I want to give him a like new experience to the phone. Also to start from the very beginning of the rom, like signing in to the google accounts and what not (like a new phone or like the very first time when you install a custom rom). Rather than just making it complicated for myself, I want to ask you, the experts. How would you solve this issue? And also what would be the best option for this problem that I am having? I just want to thank you guys in advance for not only your time and patience, but also for the future advice that you're giving me.