In article ,
"Andy Pandy" says...
I've got a gutter downpipe which is blocked by leaf debris, I think near the top
where there is a sharp angle in the downpipe. It has probably been building up
for years. Trouble is it's in a position that is almost impossible to get a
ladder to.

Is there anything I could pour down the downpipe which would dissolve the leaf
debris (without of course dissolving the plastic guttering)? I can get liquid
into the gutter easily enough from the skylight.

brick acid?