K well Poison Sumac oak and Ivy not the same leaf but basicly the same Rosin oil. Washing off in ten minutes doesnt work. To late, staying out of it is only way. I found out the hard way In Poison Sumac a couple years ago. Doc had to put me on stronger Steroid dose than a cancer patient! I had a indian friend in Wis tell me Lysol concentrate not spray or other. Hard to find. He swears shake can till it foams remove cap and spread on infected area with a finger! Burns like crazy for a bit but seems to remove rosin from the area! Good Luck, Poison weeds are miserable!