How to treat feathers

For the past 3 years, I have donated my Peacock's feathers to the local schools.

The middle school has used them for hands on science (touch, see, examine patterns, compare to other birds feathers, etc.) The High School uses them for craft projects of all types. It's amazing some of the ideas they come up with. I have also given some to friends for their projects.

This year, I would prefer to treat them first since most people do not know how. The science teacher chose to keep them as is. The High School teacher found a way; but I have not asked. Rather than wait 2 more weeks for school to start, thought I would ask here. Since they barely fit across my back seat, I know it would be hard for anyone else to transport them back n forth just to treat them.

How do you treat your feathers before using them for craft projects?

Thank you!
Cheryl ~ Pea