I have several bags left over from a job last summer. The material has hardened in the bag. Can I restore it?

I also have some that has hardened what I am going to do is set the bag in the hot sun and flip after 30 minutes or so and see if this works.

The bags are not durable and easily punctured or cracked. This allows air into the asphalt which starts the curing process. I bought a pallet several years ago and about half were that way right from the store. We used them by breaking up the chunks with a pickaxe and maul. After spreading out and mixing with some fresh material, we used a 10 X 10 tamper to compact into the hole. The patch has held up very well, although with a few loose pebbles on top.