Thanks for the tips so far. Ended up putting some bicarb in her hair (it was all I had on hand) and let it absorb some of the greasiness, then when I shampooed I let it sit for a while and let it soak in. That seems to have helped. It is still greasy, but no where near as bad. Will probably give her hair a trim anyway just to get rid of any damaged ends as it has been through a lot.

Not sure how well the soap would work, I found when I tried to wash it off my hands soap did nothing, but the shampoo actually did get it off, maybe it was just the soap I was using.