When my dad was in school around 1920, he had a teacher that all the kids hated. It so happened that this fellow like other men of his day wore his hair slicked back. This guy used lard. So my dad, being the mischievous sort, executed a plan.
1. Obtain a quantity of chalk dust in a small match box.
2. Capture a fly.
3. Place fly in matchbox and shake to coat fly liberally in chalk dust.
4. Release fly
5. Repeat as often as needed
The flies are attracted to the lard and leave little track of chalk on the teachers hair.
no political point of view here. Just a triggered memory from times past.