I always suspected that these never actually cleaned anything

I must be a bit younger than you. I remember the CD player lens cleaners. Those actually had brushes that made contact with the lens and did stuff sometimes.
Of course, a gentle hand and lint-free cloth will clean the lens, too. Probably better lol
- Not all cd players had an accessible lens. A car deck had a slot insert and there was no way to get at the lens without disassembling the whole thing.
  Computer CD players also had a tray that extended so the lens was mostly hidden.
  Boomboxes and portable CD players had pop up lids where you could see the lens, but there were probably an equal number of players where you couldn't access it.

An Amish boy on rumspringa decides that he wants to experience all that the English world has to offer, so he gets a date with a girl, and she suggests that he goes to the video store and gets them a porno to watch that night, before she takes his virginity.
Later that night he shows up at her apartment with a bottle of wine and a vhs. "What movie did you get us?" She asks,
Excitedly, he pulls out the vhs and says "this looks really sexy! It's called head cleaner!"
My older brother told me that joke as a kid. It was my first dirty joke. Lol

Most blank tapes of that era had the 5 second lead-in, and that part of the tape was the same head cleaning material. I also never believed it worked and always cleaned the heads with an alcohol soaked cotton swab. Good ole days, mix tapes and mullets.