wrote in message
...
Graham wrote:

....

Better to use crp dissolving cleaners like hot caustic soda and
fairly strong acids.

Not together or it will be a waste of both.

We had the same thing a few months ago, no amount of clearing solids or
using Domestos or anything else worked.

I bought something called Buster Bathroom Sink Fresh plughole treatment,
which came in a horrid magenta bottle .

That worked. And it foamed.

Mary