Don't trust me but I did read that you aren't supposed to clean the copper that well as the Sharkbite will adhere better to a "rough" surface rather than a shiny one.
The tool only deburrs the outside of the pipe. I took a small utility knife and just broke the edge of the inner pipe to clean it up. Sort of like stropping a blade instead of forward honing, if that makes any sense to you. Basically, scraping backwards instead of cutting into the copper...just to break the edge of the inner pipe.