A trick commonly employed in TECHNIC/MINDSTORMS building is using an axle to push another axle (or some other piece) out of a tight spot. I’ve found it helpful to use another trick, however, that involves the flexible axle joiner (see below). The NXT set includes eight of these pieces, and you can actually use them to help pull axles and other pieces out of very tight spots. Unconventional, perhaps, but it works since the flexible axle joiner is rubber, offering more grip than if you were just using your fingers.
Try running a 7M axle through several double cross blocks and split cross blocks and then attempt to pull the axle out. Not that easy, is it? Next, take a flexible axle joiner with two fingers and “grab” the axle as shown in the picture below. Now try to pull the axle out of the cross blocks, aided by the flexible axle joiner. You should find the task much easier. This little example demonstrates how the flexible axle joiner can significantly increase your ability to pull out pieces, such as axles, from difficult areas.
I’ve had great success with this trick, but you should be warned that it could possibly lead to “ripping” your flexible axle joiners. With that said, I’ve never had one of these pieces rip as a result of doing the trick. LEGO pieces are the strongest elements on earth, right?