Vinegar can be used to kill weeds.

More Info: When you use store bought vinegar on its own as a weed killer it contains five percent acetic acid. This is strong enough to burn or kill some weeds that you will find around your yard. The stronger the acidity rating, the more effective weed control you will have. You should always use caution when working with vinegar, especially those with higher acidity levels. Avoid breathing the fumes, wear protective clothing to avoid skin contact, and always wear eye protection.

Another effective form of vinegar is to make a vinegar and salt spray. This combination is very strong in acidity and will sterilize the soil on which you use it. Don't use this solution in areas where there is concrete because it will lead to the corrosion of the concrete. Here's how to make the solution:

• Mix one pound of salt with one gallon of five percent acetic acid white vinegar.
  
  
• Stir this until the salt is dissolved in the vinegar.
  
  
• Add one teaspoon of liquid soap, which will act as a surfactant.
  
  
• Pour your mixture into a sprayer and spray the weeds. You can also inject this mixture into the crown of the weed.
  
  
• Repeat this process as needed.
  
  
• This mixture is very potent when it is done during hot weather. You should avoid watering the area that you spray for at least twenty-four hours to prevent the mixture from running off into your good grass and vegetation.
  
  
• Clean the sprayer immediately after using it.