Ammonia is a colorless gas. The stuff you buy in the supermarket is amonia gas dissolved in water. Usually with soap in it. Ammonia gas is unpleasant and toxic and indeed is very volatile.
I hadn't heard about using liquid dishwashing detergent (stuff like Dawn) to remove oil from stocks but it is a very good oil solvent. I use a lot of it to clean metal parts. It works well as a pre-wash spot treatment if I get oil on my trousers or shirt.
I recently used Dawn dish detergent to eliminate an oil spill/stain on a concrete driveway parking spot. I just rubbed it on generously and full strength over the whole of the stain, and then let it sit. I came back and did it again a couple more times. By the time of the next rainstorm, the oil stain was gone. I repeated the treatment a couple more times just to make sure any soaked-in oil had been removed.
Beats just about anything I've ever tried for the purpose.
