I just received a check valve removal tool from Dan MacPherson of the Coleman Collectors Forum. I have already used it to shift a very tough valve from a 400 stove. The central locking stem held it tightly in place while I heaved on it and the valve wasnt even marked when it came out. I'm very pleased with it.
David, I also have the Coleman CV removal tool, which works on stoves AND lanterns, and also found it to be a great device. I also have a set of loco7stove's NRV tools for the brassies and they are also wonderful.