Stuck valves

Send 'em to me; I know what to do with them.

But yeah file them, just the area at the valve lock grooves, and only taking off the sharp edges. If the valve will not spin, this is very difficult, so perhaps a few applications of Deep-Creep penetrating oil.This will prevent the guides from being grooved. After that, a brass pin punch and a hammer. Don't forget to make room under the valve for it to drop out, onto the bench.