i cleaned a small warehouse that had alu frames, the metal roller type rails if you know what i mean, now there is a deep gap all round the frames hollow fill of spiders eggs webs, you name it was in there, it had not been clean for 4 years, the best brush i had to deal with this was the vikan brush, but still could not get the bristles right in there, looking at the sill brush it is curved angled , so looks like it would reach into those deep recesses, has anyone tried using the sill brush for this type of work,