poison ivy questions

In a few days, I'm going to be in contact with someone who was recently exposed to poison ivy, and currently has an active rash. It would be marvelous if any of the various miracle cures actually make the rash go away Right Now, but neither of us is counting on it. I'd like to know how we can reduce the risk of transferring poison-ivy-stuff to me and causing me to react to it. (Avoiding contact with this person altogether would be way outside my price range, as a cost for this kind of risk reduction. Our time together is precious to me.)

I know the poison ivy plants are biohazard, even little bits of oil that get smeared on shoes when someone walks over the plants. I expect that's all gone by this time, after several days and changes of clothes. Or does one need to wash with something special, vinegar or baking soda or tea or something? If the blisters break, is the fluid in them a poison-ivy-biohazard? Or is it just lymph?