You may not have to take them out. There are a few other threads on here about replacing that stuff, and it's called "zipper pile weatherstripping". If it looks like little brushes, then they make a really nice snap-in that's easy to replace. I just grabbed an end of the old stuff with some needlenose pliers and pulled on it and it all came out. It slides in a tiny track in the side of the windowframe. The new stuff you just snap in place, then slide it back and snap in the next part, then slide that back and keep going until you have that section complete. It took me longer to clean out all the crap that was built up under the old rotted stuff than it did to put the new stuff in. Went surprisingly easier than I ever thought it would and the new stuff worked AWESOME.
Here's one thread, but there are others:
viewtopic.php?f=7&t=4335&hilit=felt