I still have two tape recorders (magnetophones), and many magnetic tapes with music that I listened in the old days of '70 - '80. But always at the end of these magnetic tapes I record all sorts of things, small songs made by me, recordings with my band, or strange noises.
Here in the '70 the most common magnetic tapes they were ORWO (produced in DDR - Deutsche Demokratische Republik), AGFA and BASF.
I disbanded the erasing head of my magnetophone and make some overlay but with obvious loss in sound quality. It was fun in those years to use the standard speed 4,7/9,5/19 cm/s, to change the speed with my finger directly on the tape, or turn pieces of tape and stick them with gutter. Now I have recovered these tape ends and I mixed with other pieces done digitally in last years, or unfinished songs.
I found a recording with me at age 3 in which I repeat over and over with a very creepy voice "youuu're in a booox of doooolls' ... so...this was in my head when I mixed all.