A gallon of vinegar and a few drops of Dawn, makes a great natural weed killer.
I put it in my pump sprayer and lightly wet the leaves. Best applied on a hot, dry day.
It sure did kill the stuff.
If you want to do something more permanent that would kill the soil and prevent anything from growing there, add a cup of either Borax or Salt and wet down the soil as well.
Thanks - that'll be perfect for some driveway weeds..