I don't like putting toxic substances in the ground to kill weeds. Toxins leech into soil and eventually could end up in the drinking water. I do it the old fashioned way and dig them out or pull them out. You can also rotortil them and pick them up after.
Pace yourself. Don't try to do them all at once. In the spring when we get dandelions I will pick fifty of them a day and walk away. I dig them up by the roots and put them in the recycle bag.
