This is simple to do. Put the container in the freezer over night. The next day you'll be able to get all the candle wax out.

Microwave it to melt the wax, use an oven mitt to pour it into an empty can or something. I hope that works for you.

put the container in some very hot water for a few minutes,this should loosen the wax and allow you to remove it.

I want to use the container for something because it's one of those adorable ones from anthropologie that look better than they smell. The wick is burned out but there's still a lot of wax left