Is there a way to restore dried automotive paste wax?

You might try mixing in a little rubbing alcohol, otherwise just chuck it.

See if you can get some cheesecloth and put some of the crumbs in the cloth. Hold in you hand to warm it, and then see if will come through the cloth. Use it; make sure wax and cloth are dirt and dust free.

Try running or pouring hot water over the container.

The fact that you asked this question makes you my new hero! :-)

Here’s a “McGyver”:
1. Place the wax in a plastic bag
2. Take one of those microwaveable heating pads and heat it up until it is almost too hot to handle. You can make your own with an old wool sock and rice.
3. Wrap the plastic bag in the heating pad and it should liquefy…or at least, “paste-ify.”