I never clean a top frame even on first cleans, a rectangular brush with pencil jets is almost a must for this method though. IMO cleaning top frames ( & i am very experienced with wfp ) is more trouble than its worth, but (before the barrage begins) this method takes accuracy, skill, patience, a good light pole & quality brush, but & an even bigger BUT, the rewards are massive, i have none of the troubles of others on the forum. i.e. taking 2/3 times before cleans come good, first cleans taking ages, dirty water dripping down onto glass later in day when i've left etc.etc. a good wfp'er doesn't need ANY excuses, he just needs knowlage & enough confidence not to follow the sheep.
many people think that cleaning the top frame is a must, this is totally wrong & it's even more wrong that many suppliers tell their customers this also.
tony