Originally Posted by
silentC
On the subject of cleaning old putty out vs. old silicone, I have done both and, I say again (is this the 3rd time now?) that I would rather remove old silicone than old putty ANY day of the week. Old putty is VERY hard. It is quite difficult to remove it without taking timber with it. Some times you are lucky and the old putty falls out but more likely it is like rock. I defy you to remove it without damaging the frame.
Silicone on the other hand peels off like, well, silicone off a window frame. It sticks to glass like the proverbial to a blanket but it's grip on timber is not anywhere near as strong. Why? Because timber is porous whereas glass is not. At least that has been my experience.