For fresh turkey or other bird feathers I insert the bases in powdered borax
for about 30 days and have never had a problem. Salt is an effective
preservative but is corrosive around metals and messy to work with.
There have been a variety of good suggestions for killing an existing
infestation, just remember that freezing or microwaving does not prevent
reinfestation. I also like ziplocks to isolate tying materials. Beetle eggs
are especially difficult to kill and I would keep materials in the freezer,
at least, 30 days.
Terry Whitworth