I clean my gun with hot water only. However I do apply a patch of Breakfree and then swab with a dry patch before hunting. At the end of the season when I do my take down clean up, I use copper remover(CR 10) and neutralize it with oil. Dry swab and then a light coat of oil to protect it in storage.

Never use Hoppes CR as there are better brands avaialable such as: CR10, sweets & shooter choice to name a few. It won' t damage a barrel as that is intended use, so if you desire you can use CR without worry...just don' t leave it sit in the barrel for a long period of time (wait a minute then swab back and forth with another patch wet, follow up with dry patches and then neutralize with gun oil or rubbing alcohol, follow that with dry patches and protect with a lightly oil patch for long term storage..GTG)