At boy scout camp they had an extensive list of items a camper should bring.
For poison ivy BSA (Boy Scouts of America)
recommended this.
It actually works too!
The naphtha pulls the poison oil out.
If you're allergic to poison ivy you should carry a bar of Fels Naptha soap. I didn't believe it until my grandfather and I got into it bad while cutting wood out in the woods.
I pointed at the log and said, "grampaw are we really going to just ignore all the leaves of three?
We cut up the log and I sent granny to the store for laundry soap. They thought I was nuts but I explained that the boy scouts spent much time on this topic.
My nephew wiped his ass with poison ivy leaves...