If you've got it, fels naphtha soap in the laundry aisle will help dry it out.
As per the OP, any detergent thats good with oils.
Kerosene, WD-40....do the same, acting as solvents.
If you don't know Jewelweed, it's Touch-Me-Nots.
They started growing around our deck, I let them go.
Kinda like 'em.
Plus, it's nice to have a poison Ivy treatment that's there all season,
handy, natural, and free.