I have seen a weird skin emission since my battle with what I think is strongyloides disseminated. I use wipes all of the time, and the emissions are dark like that. I think whatever liquid these things release dries up and creates what's on your Q-tip. Bear in mind, I have not yet met a doctor who will give me an ELISA test or take me seriously.
ACV and Ylang Ylang essential oil are helping tons (especially the oil - externally and internally but must be diluted). I posted about it earlier at length.