I listened to many a backward message with my old Tascam. Before then, I used to turn over a spindle, leaving the "rolled" part of the tape outside of the guid

I listened to many a backward message with my old Tascam. Before then, I used to turn over a spindle, leaving the "rolled" part of the tape outside of the guides, fast forward through the whole tape, then turn over the remaining spindle and close it back up with the tape behind the guides again. This way you were playing the tape backward, but through the back of the tape, so it was a bit muddy, but worked. With the 4 track recorder, you just mute tracks 1 and 2, and listen to the opposite side of the tape (the side not facing you) backward. Yea, I was a weird kid. But my best experiment from this ended up on VSauce, so there is that.