I bought a denim (jean) jacket for my husband. I've been trying to soften it and so far I've washed (and dried) it repeatedly, washed it in salt, washed it in vinegar, washed it in ammonia, washed it in fabric detergent.

Short of beating it with rocks does anyone have any ideas?

It could still stand up by itself.

Have you tried fabric softener with no soap soaking?
Maybe you can try to loosen the fibers by twisteing it. Kind of like you are wringing it out when it is damp. Hubby can grab one end and you the other.:)