Having prepared and sold many, many hundreds of bird skins for tying there are a few points in this thread that leave me shaking my head... again.

A simple wash in hot soapy water with a bit of Clorox will kill all bugs and their descendants.

I used to use a large "tumbler" which was just a large rotating drum filled about halfway with 50:50 dry sawdust and borax. The damp skins are placed in the barrel and it rotates slowly for an hour or so. At that point the feathers are dry, clean, fluffy, polished, and 100% safe. The Clorox is the reason it is safe. Borax does almost nothing to prevent bad bugs.

Washed skins allowed to just dry do not produce good feathers. It takes the effort of at least blow drying the feathers to get them looking and tying their best. Dried matted skins can be washed and dried and fluffed just like fresh skins.