A mixture of white vinegar, salt and dish-washing soap can help kill weeds in gravel and keep them from growing again in the same spot. The same solution can also be applied to similar trouble spots for weeds, such as sidewalks.
Mixing 1 gallon of normal, 5 percent white vinegar with a cup of table salt and a tablespoon of dish-washing soap creates a mixture that kills weeds in a few days. The solution also prevents weeds or other plants from growing in the same place again. While this solution is good for gravel driveways or concrete walkways, it may not be suitable for use around other plants.
Funneling the solution into a spray bottle can help make it easier to apply the mixture. It should be applied to the weeds on a dry, sunny day. The solution should be applied to every surface of the weed. After using this weed-killing solution, any leftovers should be labeled and placed in a dark, cool spot until it is needed for use later.
Vinegar kills weeds on its own, but it does not have the ability to keep new weeds from growing shortly after the old one dies. Vinegar alone may be more useful to apply near other plants.