Flashing back to STOCK. How to? topic

Hi everyone,

I've been using PA for a while but it's become really buggy for me for some reason. Everything is incredibly slow and I have overheating issues with a few apps (like Hangouts).

I want to flash it back to Jelly Bean to see if it will help at all, can anyone tip into the right direction on how to do this from a custom ROM please?

Thanks for the help!