While abducted in 1976 I was in a UFO when they dumped . . . Angel Hair! They had come close to Earth and took me to the engineering section to witness their 'Angel Hair' dump.
I asked what it was. I was told it was their 'waste products' which included sewage. They explained it was processed, sterilized . . . and then dumped. It looked like cotton candy you buy at the fair grounds. It smelled slightly sweet.
The Aliens laughed about it. They said they've been dumping on our planet for some time! Why not dump it in Outer Space? I wondered if perhaps they had put genetic altering microbes in it. In other words, they dump their waste and make changes to our DNA at the same time!