Commercial weed sprays work very well at killing the vast majority of weeds. But not only are commercial weed killers costly to buy, many people have concerns about the safety of such products, both in the short term and the long term. Fortunately there are a number of safe, organic weed killers that can be made from simple ingredients found around most homes.
Mix one cup of white vinegar (5 percent acid content) with one oz. of dish soap.
Add 1/4 cup of table salt, and stir slowly until the salt dissolves completely. This can take a while, so be patient.
Pour the vinegar/soap/salt solution into a spray bottle.
Spray the solution directly on the leaves of the weeds you wish to kill. Spray some of the solution around the base of the weeds as well, so the salt can get to the weeds' roots. Spray on a day that will be hot and sunny, so the sun can draw the moisture out of the weeds' leaves. Do not spray if it is windy, and be careful not to get any of the spray on the leaves of plants you do not wish to kill.
Wait five days, and look for new weed growth. Spray any new leaves that have grown. Wait another five days, and spray any new leaves one more time. After the third spraying, most weeds should be completely dead.