Ok, we just picked up a double french horn for my high school. It seems clogged or blocked. He pulled out the slides to find where the stoppage was and found a part of the horn in the later part that was causing it. Is this normal? I know I can ask the store we picked it up from but it is already closed tonight and my son wants to play it. any advise to try?

You haven't described what the part was stuck in or what the part itself was. If the part is stuck in one of the tuning slides I would advise not trying to remove it yourself as it could get stuck worse and replacement parts for French horns are not cheap nor are they easy to obtain. If you do try removing it you risk bending the tubing out of alignment so that the slide won't fit back in and be adjustable. You also risk distorting the shape of the tubing at either end which again has bad consequences. That being said if you do try; try to push the part out gently in the direction you think it entered. Use a flexible cleaning tool like the ones for cleaning trombone slides. It looks like a small diameter plumbers snake with a brush on one end and is often covered in plastic to protect from scratches. Use a gentle tapping action with the cleaner snake against the part inside the tube. If it is still stuck in there try to obtain a ball bearing that will easily roll through the tubing but is larger than the part so that it will not get jammed against the part. Drop it into the tubing. Next drop another ball bearing the same size into the tubing from the same end so that it rests inside the tubing against the first one. Hold the tubing in the hand you use the most with your thumb over the end of the tubing that has the bearings in it. Remember you are trying to remove the part in the direction it entered. Next shake the tubing so that you can feel one bearing hitting the other. Do this gently at first. You are trying to make the impact of the second bearing against the first force the part out of the tubing. Also remember that I recommended against all this in the first place. It took me ten years of experience before I got good at it. This is not normal but can happen. Usually it is a foreign object left loose in the instrument case that is the cause. Make sure that the part wasn't originally soldered to the instrument as it will need to be professionally soldered back on. Here is a link to a professional band instrument tool supplier:http://www.ferreestools.com/ Have a look at the tools and you might get some more ideas. Look in Tool Instructions. Good luck.