I would suggest you first mow down what is there if that hasn't been done already.* Then you could use either a radiant heat weeder or a flame weeder.* If using a flame weeder, DO NOT BURN POISON IVY!!!!
You might find this helpful on how to use a flame weeder.
You should be able to rent a flame weeder, but you would have to purchase your own propane tank.
When weeding, the best way to make sure you are removing a weed and not a valuable plant is to pull on it. If it comes out of the ground easily, it is a valuable plant.