Just run RUU. Download the RUU file to your computer, hook your phone up to it and then run and follow the prompts. It will put it back just like it came out of the box. Keep in mind you have to relock the bootloader first to run RUU. See the below with links to the RUU files. Just download the EXE file for your carrier.
AndroidFiles RUU
Alternatively, you can follow the below thread with a couple methods to get back to stock including running RUU.
[GUIDE] Complete Flashing Guide | Rooting | Going Back To Stock | 05.05.2013 - xda-developers
I personally prefer the RUU method to get back to stock. Just gives it a clean slate feel. Good luck.