So, I've been playing a Marcinkiewicz Rembrandt for jazz gigs for the last 2 years or so. I bought the horn new, and the 3rd valve has always dragged a slight bit. Not enough to send the horn back, but just enough to be annoying at times. I thought the valves would loosen up over time, and they have a wee bit, but the 3rd valve still bothers me. However, I was reading another thread about sticky valves, and someone mentioned that one of the valve vents could be clogged. I've been playing the horn for 46 years, and didn't even know valves had vents! So cleaning my horn tonight I blow into the bottom of each valve. To my surprise, the venting of valves 1 and 2 is quite open, but there is a lot more resistance in the venting of valve 3. Could this be my issue? If so, what do I do about this?