Boil a pot of water, then immediately pour the boiling water onto the weeds. The scalding water will burn many types of weeds, preventing them from repairing themselves. Do this treatment two or three times over as many days, and the weeds should start to die off.
Pull them out by their roots. Get as much of the root structure as possible to ensure the weed does not reappear. Using a trowel to dig them up can help you remove the root entirely.
Pour white vinegar on the weeds during sunny weather. The sun will interact with the vinegar and kill the weed completely. This method will also kill any other plant the vinegar comes in contact with, however, so be careful when applying.