This is what you use to remove the nut:

http://www.askmehelpdesk.com/attachm...-20remover.jpg

but I don’t trust compression nuts, especially when the end of the pipe gets messed-up trying to remove it so when I do remove them this is what I solder on to the end of the pipe:

http://www.homedepot.com/catalog/pro...1b1d44_300.jpg

You will be glad you did especially if you have expensive hardwood floors and take long vacations.