Drysuit owners:

Another note on the use of talc: The functional layer of a Gore-Tex garment is between two layers of fabric (I think bonded to one of the layers, but I’m not sure). Dirt that’s ground-in to the outer fabric could affect moisture transfer, but I can’t see a light dusting of a material on the inner surface that falls right off, or washes right off, doing any harm. And if it really helps prevent the adherence of body oils to the inner fabric, it should be promoting functionality, not hindering it (but I won’t speculate whether or not it really is good for preventing body oils from getting into the fabric (for myself, I make sure I have good coverage of clean liner clothing with that goal in mind)).