Just been out today, had a gutter clean booked in, fortunately Mr Parcel Delivery Man delivered my much anticipated package of Ecover Truck Wash from Mr Gardiner about 20 minutes before I left.
So armed with my new cleaning fluid off I trundled out into the wet of an English Summer.
The gutters that were due to be done were pretty bad, not the worse, but with a good, thick, dark green covering of Algae. The sort that would require a stiff brush with possible real stubborn patches needed extra scrubbing and attention.
Anyway, to apply the Truck Wash I had one of thsoe garden sprayers, capacity of about 3 litres, and sprayed it on whilst I was up the ladder cleaning the gutters out. Came down, and then WFP'd the outside of the gutters.
I was really rather pleased with the result. After allowing it to soak into the lagae for no more than 5 mins the stuff came off really easily. Once over with the brush and then back again literally they were gleaming. Well impressed.
Ill be making a 20' foot lance to rig onto the garden sprayer I have so as to be able to apply this stuff with out laddres.
I used (heavens above) my new single trim superlight brush for the job, mainly as I figured it would be the best brush I have for getting up behind the gutters due to the bristle length and also as theyre the softest bristle I have the best for getting right in behind the gutter brackets. Also on the way home it occured to me that being that the bristles on this brush are fairly soft how easily the gunk came off the gutter, if it had been a Vikan I reckon the stuff would have fallen off with the brush just looking at it

Well done Jeff, well sourced, cheers Alex.
Matt