I think I've found something that works well.. Floor dry as we call it or absorb all. The stuff to soak up oil off the floor.
It's dry and dusty out of the bag but using a garden hose on mist nozzle position I wet it down and mixed until I got the consistency or I guess level of absorption that isn't dusty or water logged and it looks like dense material but is still light and should be easy to dig? I mixed up a batch at work the other day, hope to make a batch at home this weekend. I'm wondering how it will dump out of the trailer? Not sure if it will stick or slide? Ill let ya know when I find out
Mario