I haven't tried this but plan to - shove a knife (or serrated root cutter) straight into the middle of a dandelion, push it slightly aside, then pour distilled vinegar into the root. This is supposed to kill the dandelion over time.

Here is a little story that may help change the paradigm on dandelions.

A dear friend in El Paso was hosting two German women. She toured them around the city, showing them all the fine points and fun places of El Paso and its sister city, Juarez, Mexico. But the only thing any of us remember about that visit many years ago, is the women's delight and enthusism over " the beatiful yellow wild flowers in the lawns!"

Wouldn't a garden border of dandelions be bright, lively, nearly indestructible, a delight to kids of all ages...along with providing tasty and nutritions greens for your salads!

Hi. Simply pull the dandelions out. Do not worry about "getting the whole root". Most of the time you will. Each year those will root remnants will come up, but weaker, and you pull again. In a very short time you will only be pulling less than a half dozen each spring. The only time it bothers most people is when they flower then go to seed early in the growing season. "Weeds" are diversity not enemies. Any plant you don't like, simply pull out. Again, if some root remains, the plant is going to be substantially weakened anyway. Pull again, and it's done. Very very simple. If you have lots of plants you don't desire, loosen soil with a shovel, and rake out plants. New seeds will germinate, hence the first method is preferrable: pull out any undesired plants. If you are not strong, just pull out one or two a day, and believe me, you will soon make good progress. Again, undersired plants are not enemies, but diversity. In your own garden , you choose what you want, but please apply hand labor, not chemicals. Even vinegars and salts will build up in the soil.
Be cautious and have fun!

Corn gluten is fine for some people, but not for anyone who is allergic to corn or the sulfites that are used to process it. I am allergic to both corn and sulfites, and many other people are also allergic to them, or have asthma and can't tolerate sulfites. Otherwise, the gluten would be a much safer choice then herbicides.