You can also get rid of them and reuse them. From time to time it is difficult to obtain the previous nut and ferrule off on the pipe; In such a case, you can remove them by using a compression sleeve puller. Compression valves are available for small prices at https://sparkyd073lop3.thechapblog.com/29789553/the-fact-about-bathroom-angle-stop-valve-that-no-one-is-suggesting