|Betsy is absolutely correct. I have 700 acres of gold claims in Northern California, the most infested area in the west with Poison Oak. I have had it probably 20 times, twice which required "Kenalog, a steroid shot" to control it. It is not necessary to discard the clothes (DO NOT BURN). Wash them two times in a heavy detergent such as Tide.
When we get done with our claim work, we immediately put all the clothes in a garbage bag and take a cold shower with lots of soap. Wash from your head down. The cold water prevents pours from opening up and entering your blood stream. When ready to wash the clothes, remember anything they have touched will have the Urushiol oil on it. Wash your hands after handling.
Hope that helps, and yes, we get alot of gold so the Poison Oak is our enemy, but we cannot get the gold without the poison oak.