"John Rouse" wrote in message
...
In article , TheScullster
writes
I intend to remove the blue/grey stuff which is very localised (about 1
sq
metre) and looks the most unhealthy.

I've been digging out a lot of the "pot clay" (yellow in our case) which
someone kindly dumped under our drawing room floor (don't ask!).

My curiosity insists that I must ask.

[snip]

Franz