On 20/09/2017 13:02, Andy Burns wrote:
alan_m wrote:

Block off the bottom of the pipe and fill the pipe with water. The wood
may float up to the top.

Get a GBFO LPG torch, play the flame into the 'shoe' the chimney effect
should carry the flames up inside the downpipe, sit back with a beer
then wash the ashes out with a hosepipe!



Tempting, but that would wreck what paint is on still attached to the
pipe and (probably) accelerate the internal corrosion