First of all, I realized I'd been saving a lot of old candles - just waiting for big old batch of cleaning.
The wax in the ones on the far right and far left have already floated to the top. You'll be tempted to empty them now, but then you'll have a waxy, watery mess in your sink. So just wait until they cool completely.
I stuck an old butter knife in the rest of it:
And it popped right out:
The others broke apart easily.
Here they are, cleaned and ready for re-purposing.