I'm absolutely surprised that you don't clean the top frames Alex, I personally don't think it's the way to go, even when your really careful, you can splash it, and still get a run, but if you spend one clean properly on the frames, then they do come up very nicely, only been doing wfp for 2 weeks, so yes I know I'm still wet behind the ears, but it works very well for me, no problems!
And once you clean em well, it's just a matter of keeping them clean. Looks brilliant to see all of the frame sparkling.