Andy Dingley wrote:

My local plumbers merchant gave me a jar of sodium hydroxide,
and told me this was as good as anything.

Waste of time. Caustic soda is good at shifting kitchen fat blockages
in a fairly dry pipe. But for toilets, go for an acid cleaner instead
- cond sulphuric should be in ny decent plumber's merchant.

Well, I have to say - the caustic soda worked.
I left it overnight, as advised.
In the morning the toilet did not appear to be clear,
but I poured about 10 litres of very hot (80deg C) water down,
again as advised, and the blockage suddenly cleared,
and now the toilet appears to be as good as new.


--
Timothy Murphy
e-mail (80k only): tim /at/ birdsnest.maths.tcd.ie
tel: +353-86-2336090, +353-1-2842366
s-mail: School of Mathematics, Trinity College, Dublin 2, Ireland