Chromatic harmonica slider becomes less smooth after playing for about 30min

So my solution was vaseline. In SCX 64 (should be true for SCX 48 and 56) the spring goes through a hole on the slider and is held in a concave space located on the mouthpiece. I applied a tiny amount of vaseline on the slider and mouthpiece in those areas. I also applied it on the slider near the button. Now it has been one or two weeks and the slider NEVER got stuck again.

I tried to keep the amount of vaseline as little as possible to avoid any bad thing it might bring. (e.g. melting or making the components greasy)

A bad news is I accidentally folded the draw valve on hole 16. Now it needs a bit more air to draw that B note. So be very careful when you handle things on the reed plate.

Good luck. :)

I've had issues like these too, the problem is u really need to use slide oil. That's the only way to solve this problem. Most harmonica comes with slide oil inside it, after using it for some time (depends on the quality of slide oil), the slide oil will run out and you'll have to apply slide oil again. That's what slide oil is for.