| Clue | Source | Date |
|---|---|---|
| Streaks from a soccer field, perhaps? | ||
| Green smudges on jeans, perhaps | USA Today | 07 Nov 2017 |
| They often turn knees green | New York Times | 14 Jan 2017 |
| They often turn knees green | ||
| Green smudges on jeans, perhaps | ||
| Prototypical laundry challenges |