Ninety nine percent of jars can be opened with ease, once you release the vacuum. To do this, get a old style can opener with a hook and gently lever the edge of the lid until you here the air rush in. Or use a blunt table knife and gently prise the lid to release the vacuum. Then the lid should turn with little effort. If you do not wish to keep the jar just puncture the top of the lid to release the vacuums grip.