B.M.
I live in the woods w/ PI and no way to eradicate it completely. I use Felsnaptha laundry soap to wash my hands and arms (and whatever other body part). If I DO get PI I make a lather and leave it on the area to dry. It helps and is less expensive than a lot of other remedies. Also is great for stains or to wash the oils out of the clothing...
Don't let it get out of hand though. I've had PI so bad that the Dr didn't even know what it was and had to go to a dermie...got put on steroids, etc., and ended up w/ scars.
Nip it in the bud !xo