Drumroll please...the secret is...VINEGAR. Can you believe it? Who knew. I mixed 2 parts vinegar with one part water (ie 2 cups vinegar 1 cup water) and put it in a spray bottle. When I was done murdering the broadleaf weeds in the yard I then added 3 tablespoons of salt, swirled it around the bottle and sprayed it on the cracks in the driveway...worked like a charm. Just remember if you add salt, you will kill your lawn (for some reason the vinegar doesn't kill plain old grass).
Now go make your yard smell like paint-dying easter eggs!