A number of cases described a reddish clay residue that had been found at abduction sites.

When I was a child I lived in a corner apartment on the first floor in New York state. One night when I was about eight years old, my mother had just left my room after tucking me in. About five minutes had passed when I saw a shadow of what looked like a thin man with no hair walk up to my window. The curtains were drawn shut, so I could not see detail. I was startled, and then I heard a scratching noise against the screen. I was so afraid that I couldn't move. I tried to scream but nothing came out. Finally, I was able to get out a yell and my mother came rushing in. I told her what I saw and she reasured me that there was nothing there and that she would take a look. She kissed me goodknight and left the room, with the door open this time. Later I could hear her talking with her boyfriend outside my window. The next morning I went outside and took a look at the window. There was a reddish, pinkish clay that had been smeared about 5 or six inches on the screen where I had seen the shadow. When I asked my mother about it, she didn't say anything.
Years went by. It was always in the back of my mind, but I didn't dwell on it. Then in the mid to late '70's I saw an episode of "IN SEARCH OF" with Leonard Nimoy and the episode dealt with alien abductions. A number of cases described a reddish clay residue that had been found at abduction sites. After I saw this it was like a light bulb had gone on. It made my hairs stand on end. To this day I often wonder if I had a close call with being abducted.
Date is approximate.  Source elects to remain semi-anonymous.  PD