Black Diamond Blasting Sand Oil Slick
I have washed this blasting sand numerous times. I let it sit for several days in a bucket and it all looked good to go. I stirred it up a bit and I got an oil slick. This time is my second batch. I actually washed with some dish soap.
My first batch has been put in the tank already. The oil slick doesn't affect fish or plants, but just looks bad.
With or without detergent, the slick is still there...Any pointers? I mean it's just coal slag