Hi all, I have an old B&H Sovereign cornet (1970s I guess), nice machine, good nick in general and well looked after. Recently however, I have noticed that the valve action isn't as it used to be. The valves don't stick as such, they just aren't as smooth when being depressed as I'm used to, a bit like when oiling is required. However, oiling and full cleaning fails to improve things, so I'm wondering if more radical action is required. So, any suggestions anyone? Does anyone have a sure fire solution - is this something I can cure, or is it a job for a pro? Any thoughts or suggestions gratefully received. Many thanks.