I was able to iron this out best I could without taking the 3rd valve slide off or using a flatter magnet (before/after):


I am fairly pleased with that, but the 3rd valve slide had a serious, super duper sharp pinpoint DENT in it. I am pretty sure it punctured the brass. You can see what that very, very sharp dent did to the inner slide tube when they tried to pull it out:

It was actually firmly stuck when I received the horn and it took some heat and penetrant to get it out. It's just a mess, and actually worse than the pic looks. The tubing is completely out of round and nearly conical. It's like that on both sides, since I guess someone tried to flip it and force it in the other way.
After I fixed the dent in the outer slide tube and filled it with a dot of solder, this inner slide tube would not go in past a certain point. I could have ordered a new part, yadda yadda, but being budget-concscious for the program, I offered to cut the slide short so that it still had a respectable amount of pull but to get rid of all that damaged tubing that looked like a zig-zag frozen french fry pattern. I cut the slides at a certain point, flipped the inner slide so that I was able to hide a bit of the ugly chewed-up part (and the part that I cut, not worrying too hard about complete symmetry) underneath the ferrule, smoothed down the solder marks on the end, and reinstalled. Bingo! The 3rd slide is so long that there is still ample pull if it's ever needed. I find on my Besson Eb I don't really have to pull that slide at all.
Still needs a bit of clean up, but it's almost ready. Overall, a fairly simple fix that just needed a bit of head-scratching to figure out what was best for this situation.

