Question
I just moved to an apt. with a large patio. Already on the patio were four oversized plastic pots (like the kind you see on street corners) with mainly weeds growing in them.  One had a creeping ivy that turns out to be poison ivy (I have it now!)   I would like to use the container, but I'm not sure how safe it is to remove the ivy, and do I need to discard all the soil too.  How do I make the pot save to use for other plants.  Thank you

Answer
It is very unusual to have poison ivy spread to a container.
Use caution to remove it. Wear protective clothing and gloves. Put the soil and plants in large plastic trash bags. Leave the soil in the bags until the weeds have died. Discard all of the soil in all of the containers. The weeds have depleted the nutrients and spread seeds, so it is not good soil. Clean the containers with bleach water to get rid of any contaminants.
Use a very good potting soil, and fill the container to the top. If the containers are very large, and you don't need the soil that deep, use a "filler" like the Popcorn Packing chips, or another pot upside down, or some other type of cheap filler. This will save your potting soil for just where it is needed.