Mix up a nontoxic weed killer by combining dish soap, salt, and vinegar. Add one tablespoon of dish soap and one cup of salt to a gallon of vinegar. Pour it all into a spray bottle, and use liberally on problem areas. Remember that this solution is nonselective, so be careful not to get any on your grass or landscaping plants, as it will harm them as well.
Related: 7 Weirdly Effective Ways to Weed