I was very, very surprised to read that one of the least harmful ways to rid an area of plant life is to pour boiling water on them! My husband, a horticulture major, was not.
I learned of this method of cooking weeds to kill them in several top ten lists of ways to be environmentally savvy. It’s one of the best methods of killing dandelions, as one can poke with a thin pole several inches into the dirt, then pour the boiling water. Sugars added to the water, keeps the water at a higher temperature, however, adding sugars to the water is not recommended for home use as sugared water is obviously attractive to some insects, and would be slower to cool on your skin should a spill occur.
Some sites advocate adding salt to the water, but salt is a natural toxin. Several years ago (about 5 or 6) in an attempt to keep the creeping ivy out of the packed-dirt space beneath my barbeque, I poured salt around the perimeter of the patch. Years later that ivy is still not encroaching on my space but I wonder if the soil will ever detoxify. 
If you are boiling weeds in the middle of your lawn, such as dandelions or other long-rooted plants, you may want to scatter grass seeds over the boiled area the next day. Always, always use a teakettle or other similar self-closing device and wear an oven mitt or glove. You may have learned to pour water from pasta without hurting yourself but this is a whole different angle and type of pour. Never carry an open container of boiling water.
If you are living in a drought or desert area where water is scarce, you may enjoy this tip gleaned from our local television site. Kron4 advises you to catch the cold water in a clean bucket as you warm up your shower in the morning and use it later for things like rinsing dishes, watering plants, or, in this case, eliminating the weeds! And just maybe, if you are using potable water, you may have enough left after weeding for a celebratory cup of tea!
Dandelion Photo courtesy of: Wadester16