One year up in Ontario, there was an enormous "dock spider" that was in the middle of our dock steps every day. We named him Martin. The 2nd day, I was playing around with the under-dock fishes - perch, juvenile walleye, etc - with my fly rod. They jumped everything I threw with enthusiasm...until I tossed a big leggy spider pattern. They'd rush over, eyeball it from a foot away, then flee in terror.The ones that creep me out are the big "fishing" spiders with muscular legs that look as big as fingers. They are grey like rocks and not afraid. ((shudder))
Found this site....https://www.theessentialfly.com/blog/so-why-is-cdc-special-for-fly-tying-and-fishing-flies.htmlI have read that it's the structure of the feather that gives it it's floatation properties not the oil so you may gently clean them if you wish. That advice, if I remember correctly, came from early CDC expert Shane Stalcup (R.I.P.). Try googling his name and see what you get.
I have a couple of Shane's vids that include bonus segments on the care of CDC. He's really underrated as a fly tyer in my opinion and largely forgotten. His gilled nymph tyed in callibaetis colors was responsible for my second largest stillwater fish. He really pioneered the use of synthetics in realistic looking flies. Every fly tyer should have his Mayflies: Top to bottom book in their library.Found this site....https://www.theessentialfly.com/blog/so-why-is-cdc-special-for-fly-tying-and-fishing-flies.html