This weed killer is easy to make with things you probably already have at home. I get asked a lot about killing weeds "safely". I personally think all weed control is safe if you follow the label and wear your PPE, but here is a good option for those super concerned.
Mix:
1 gallon distilled white vinegar
1 cup of table salt
splash of dawn dish soap or surfactant
Round up sprayer: https://amzn.to/2XjJ7Yo
My4sons backpack sprayer: https://thelawnwhisperer.net/products/my4sons
Cool season lawn care guide: https://thelawnwhisperer.net/products/e-book-the-lawn-whisperers-guide-to-cool-season-lawns
The whisperer pack (products I use on my lawn): https://thelawnwhisperer.net/products/whisper-pack