I'm finally getting around to replacing our downstairs bathroom sink after procrastinating for a couple of months. The actual replacement is not a big deal (I hope) but shutoff valves are 40 yrs old and shot. They are compression fit on 1/2" copper in a tight location. Removing the old brass compression ring could be a hellacious job. I tried reusing them with the new valves, but the joint weeped. They are too tightly on to remove with channelocks, so a dremel tool or hacksaw cutout looked like the only options. 
And one was so short that the nut covered part of the compression ring meaning that I would have to be cut out first. 
I thought about leaving the old rings in place and soldering on a new stub but that would be pretty visible. As I was picking up some 1/2" couplings I griped to the store guy and he pointed out to this tool. I tried it and voila. The compression rings were off in a minute! If you are ever in this situation, this simple tool is da bomb!
![[Hearth.com] Plumbing, removing an old compression ring](https://www.hearth.com/talk/data/attachments/328/328099-dfc42258d946ae9dd6558b95c4081c7a.jpg?hash=wUhkUvZmre "[Hearth.com] Plumbing, removing an old compression ring")
And one was so short that the nut covered part of the compression ring meaning that I would have to be cut out first. I thought about leaving the old rings in place and soldering on a new stub but that would be pretty visible. As I was picking up some 1/2" couplings I griped to the store guy and he pointed out to this tool. I tried it and voila. The compression rings were off in a minute! If you are ever in this situation, this simple tool is da bomb!
