On Thursday, January 12, 2017 at 5:50:24 PM UTC-8, John B. wrote:
On Fri, 13 Jan 2017 10:17:20 +1100, James
wrote:

On 13/01/17 08:33, Phil Lee wrote:


But in this case, there is already movement in the cup - all that's
needed is a little extra space for the movement of the cup in the
bracket shell to allow the corrosion to be ground down a bit finer by
working the joint back and forth.


I wonder whether a couple of hours soaking in a solution of CLR (Calcium
Lime Rust household cleaner) would help?

I had never come across CLR. How effective is it in removing heavy
lime deposit in pipes?
--
cheers,

John B.

You're not supposed to drink it John. There are other products which will clean out your pipes.