I also use a blue dye in the pump sprayer. It can make quite the mess if you are not careful and steady handed.
The most important thing I have discovered about handling it is to rinse the bottle off after every pour. If not it tends to spread like a COVID virus = everywhere!
It does go away in the sunlight after a few days but is great at saving time and herbicide usage since you know what was sprayed!
I have wiped out some invasive non-natives by pulling and propane torch burning (beggar’s lice/Torilis japonica (Hedge Parsley)) was about a five year battle to get it nearly eradicated. For herbicides it has been Johnson grass, Chinaberry trees and currently in a battle with KR Bluestem. The trees were pretty easy and the Johnson grass took a good three years to get under control but still see some spring up every couple of years. The KR bluestem is difficult to keep up with, it spreads quickly and looks like other grasses in the field until it goes to seed. But I will keep after it until either it or I are gone.