Remelting the wax is always a good shout, and you might do this in a variety of ways.
Another way to use boiling water is by pouring it into another container and submerging the jar instead.
The wax seems to melt much easier this way.

AsBetter Home & Gardensnotes, the process of freezing shrinks the wax so it should just pop out.
Another trick to getting wax out of an old candle jar is by using more direct heat.
Before cleaning the container for further use,Cleanipediarecommends letting it cool before cleaning it with washing-up liquid.
