Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

There is one method that will work:
Use a large wire cutter pliers and try to get under the loose collar of the valve.
Then try to cut but dont cut it off...
Repeat this at different angles to get the neck thinner until it comes out of the boiler.
Always hold the backside of the pliers tight against the boiler to prevent bending out the hole.
The valve will finally come out... the worst that can happen is that the inner soldering ring of the valve may get loose and will fall into the boiler. Usually you can cold the boiler overhead, pick the ring with a needle nose pliers and bend it that it will come out through the same hole...