Lid stuck in wedgewood jam dish?

Wedgewood cabbage design white jam dish. Lid is stuck very firmll inside at an angle with the knob jammed against the side of the dish. we have tried, heat, cold, ice cubes, washing up liquid and oil, but it won't budge. Does anyine have any ideas
Liz hope smith, January 2012


done
why not email the factory they may have a solution

tango nancy, June 2012