how about instead of a dual trim brush someone makes a combi, bristles that splay well on the outside for the corners, frames etc and then for the glass the white scourer (where the shorter bristles are normally) after all we are all told its about rinsing rinsing rinsing, so once the dirt is shifted it should be a good brush to rinse on with,
probably no good for leaded though, but i change brushes for that anyway!