If you're worried about harming your grass with chemicals, use broadleaf herbicides instead of non-selective herbicides. Broadleaf herbicides target the broadleaf weed without killing your grass. A non-selective herbicide kills any plant it comes in contact with, regardless of whether or not it's a weed. If you spray it across your lawn, you will kill your grass. Non-selective herbicide is effective when used for spot-treatments, such as killing a few dandelions growing along your walkway.