What's a good diy weed killer?

Where is it for?

If you're trying to kill weeds in gravel or sidewalk cracks sprinkle rock salt and water it. The weeds will die and disappear.

Epsom salt, vinegar, and water. Safe for the environment, and works wonders on weeds

Round Up

I use straight vinegar, epsom salt followed by boiling water or just boiling water . . .

Salt or agricultural vinegar (available at plant nurserys)

Epsom salts and white vinegar, just do not use in a flowerbed or vegetable garden.....otherwise use a product like Preen

It could kill grass too, but here's a link to another weed killer that won't kill your grass:

http://www.ehow.com/how_7173768_homemade-weed-killer-safe-grass.html

It could kill grass as well, but I've read that corn gluten meal is another option that won't kill your lawn.