On Wed, 25 Oct 2017 10:32:47 +0100, wrote:


You might be able to get the worst off with a sacrificial wood chisel
but it will take forever to do and be hard to do neatly.

Somebody else is fitting the stove today so I'll need it work around it
at my "leisure", whatever that is ;-)

Too late to try a heavy duty pressure washing then, it seems to have
got a lot of city buildings much cleaner since decades of soot from
coal fires has been washed off. Buildings in London and other cities
just looked black and depressing back in the 1960's.
Quite messy to do though.

G.Harman