A number of organic gardening catalogs sell vinegar-based herbicides, usually with soap and/or lemon juice added for extra sticking and penetrating power. You can also make your own, using the recipe below. In a pinch, plain supermarket vinegar, either distilled or cider, effectively kills many troublesome weeds, including spurge.
Try this herbicide recipe that comes straight from the kitchen:
1 tablespoon dishwashing soap
1/4 cup salt
1 quart vinegar
Mix all ingredients together and spray on weeds.
You can also spray unwanted plants with rubbing alcohol. Try this solution:
2 tablespoons rubbing alcohol (use more for really tough weeds)
1 quart water
Regardless of the ingredients, apply the potion with a spray bottle and coat the plants thoroughly. Weed-killing works best on hot, sunny, wind-free days.
Source: Sunset Western Garden Book