I'm a novice at jam making but successfully made some mirabelle plum jam a few days ago. To use the remaining plums I made 2 jars of brandy plums on Saturday night. I realised I had run out of jars and bought 2 cheap Kilner-type storage jars from the supermarket but am now worried that they were not proper preserving jars, as the jars have not sealed. I sterilised the jars and rubber seals. I followed the recipe...filled the jars to the brim and clipped the lids closed then left the jars for 24 hrs to cool upside-down. Last night I checked the jars and the seal was not tight at all. I then got distracted and unfortunately forgot to put the jars in the fridge. Now I need to save the situation - Will they be safe to re-process/re-seal? Do I need new jars?