I have a sovereign euphonium, with a stuck slide on it. If you look at the euphonium from playing position, i.e. from behind, there are tiny slides out of the valves. This is for compensation (I think). Anyhow, the slide on the first valve is stuck, because I put in in the wrong way (probably months ago, I only noticed it now). Its been put in at an angle. I put a piece of cloth through it and pulled. I cant get it to come out. What do I do?