Ants often bring aphids! They love the sweet secretions that the aphids make. Aphids, needless to say, are not good for your plants. Some ants grow fungi to eat. They cut leaves to grow the fungi on. Again, bad for your plants. I would stick the soil in a black bag, seal it and let it "cook" in the sun for a few hot days, turning every now and then to "cook" evenly. - Granny:hippy: