A teaspoon full might be a bit much...…. interesting that the OP still had pressure in the system after unscrewing the Schrader. This is the pressure that has got in behind the (unvented) inertia weight I suppose. Out of sheer nosiness 10/10, did your inertia weight have a small hole drilled through it or not? I remember Rhyslightnin and I having to drill a hole in his in order to relieve pressure and allow us to strip the rest of it all safely.