Are Disketter cleaning kits useful? (particularly for an old working Disk ][)

I haven't used one in years, but it seemed to work fine. A can of compressed air got out the big stuff just fine, but the cleaner never hurt anything.

I Found a diskette Cleaner on clearance for a buck or something and bought it because they are hard to find these days. If your floppy drive goes unused for weeks or months at a time (like mine do) a cleaner sure comes in useful.

Cleaning diskette ordered. Sounds like cheap insurance.

Cleaning disks become most useful when you copying a bunch of old floppy disks that are dirty or have loose surface oxide. If all of your disks are new, and the disk head is clean, you won't need the cleaning disk very often.

I have manually "spit shined" the disk head and performance has improved. It's able to read a new old stock Pacman game that would not boot up earlier.

Used a cleaning diskette and now my Zork which was not booting up, boots fine!
This is just after one applicable and AFTER i thought I had spit shined it after dismantling.

I am sold on diskette cleaning kits for Disk ][ drives. No snake oil here.