The Natural Philosopher wrote:
Chris Bacon wrote:
The Natural Philosopher wrote:

I simply fill the plughole up with neat dry caustic soda, and dribble a
kettle of hot water on it.

weary sigh

Take advice on this, from the Internet at large if need be.

Hint: you might have complete success, or block up your
plughole, or cause yourself permenant physical disability
by blindly (cf) following this advice.

another weary sigh

Well I have used it vonsisten;ty over 30 years or so and have not blinded
myself, or blocked up a plughiole, yet, ever.

But it's knackered your brain/finger co-ordination, by the look.

If lavenders19 should try to use this method, which has nothing to
commend it over using a made-up solution of "caustic soda", then
if I were him I'd take precautions, such as using eye protection,
having a couple of full pails of cold water at hand to wash in
if necessary (the sink being a no-go area), as well as a good supply
of vinegar to finish washing in. Oh, I'd read the instructions on
the container, too.

No - cancel that. I'd ask you, with your 30 years or so of experience
to come and do the job, after getting you to sign a disclaimer.