How do I open kilner jars that have been sealed for 5 or 6 years and refuse to open? They contain bottled fruit. Will the fruit be edible if ever released?
if the bottles were sterilised properly and also the sealing process done correctly they probably would be.
Do the hinges not work on the seals or something, try WD40.
They should have the red rubber gasket - with a protruding tab? If so - use a pair of pliers to pull the tab horizontally away from the jar and the seal should go. Remember to preserve the gasket for next years crop!
Since they haven't exploded in that time, you can take it that the contents were properly prepared, and should be perfectly edible. If Maxi's method fails, try placing the jar in a bowl of warm water up to the neck, and gradually increasing the temperature of the water. This may allow the contents to expand enough to make it easier to release any vacuum.