Green stains: advice from grandma

Do you recognise this? Your children have put on brand new or clean clothes. You’re about to go to this party. You’ve warned them to be careful; just this once…

And after about 3 minutes, they return with sad faces.
Dropped on the grass. No pain. No injuries. But… green spots on the knees.
Grrrrr.

Of course, you won’t get angry with them. Your child should be able to be a child and therefore should be able to play happily outside. But it surely is frustrating.
Right?
All the more so because you know those grass stains are difficult to remove. And we’re talking about extremely difficult. Like: Even grandma won’t know what to do.
The risk of grass stains on the knees is eliminated by artificial grass.
Let them wear new clothes and they can still play soccer, make slides, romp around or bore the dog. There’s a 100% guarantee that your kids will go to that party without any stains!
If artificial grass existed back in the days, surely grandma would have known what to do about grass stains: She would have written down “Your own fault”. “You should have installed artificial grass…”