I have several old windows with 4 large frames fitted in them. How would you deal with the streaks that are bound to occur with the dirt seeping down on to the bottom 2 frames? I could simply not touch the top frame to avoid it happening to the top 2. Thinking about it I reckon the answer will be do the top 2 then the bottom 2 later as mentioned in a recent thread. But what do you do with falling apart putty/wood frames?