Cleaning old pipes when jointing

[RobinClay]

When T-ing into old tarnished copper pipe, I have always scoured the pipe back to a bright finish for a soldered joint. But how important is this for:-
a) compression fittings? and
b) push-fit ?
How well do they seal onto a tarnished pipe ?

I have been "scouring back to bright", but am I wasting my time ? It's a real pain when the pipe is difficult to get at anyway...

And how much does that scouring actually reduce the diameter, making a leak more likely ?

 

[TeaTime]

Cleaning back to bright metal should always be a best practice really, it ensures there are no bumps / scratches in the pipework, or leak paths underneath the olive, I assume this is the same for the sealing face of a pushfit.

I know it's a pain in the neck, but it's best to do so. At least if there is a leak, you can always rule out poor pipework finishing.

As for the wall thickness, unless you are looking to use a 36 grit polishing pad, I can't see it being an issue. I mean, how many times are you going to be going over the same length of pipework?

 

[longdogs]

I normally use some Scotchbrite for cleaning up copper pipes. I would say that it is as important with push-fit and compression as it is soldering (ok, a bit more important for soldering). It's really annoying when a push-fit fitting gets stuck half way or an olive is hard to slide on because it has crud under it. It also shows up any small indentations in the pipe which might cause a leak.