Severe drop-outs on a recorded tape (not prerecorded)

Hello everybody,

I’m sorry if this topic has been already discussed here.

Unfortunately, I have 2 or 3 blank tapes (recorded by myself in the 1990’s) that they have really severe drop-outs.

There is absolutely no sound for 2 or 3 minutes or sometimes you can hear really some small parts of the recording.

My guess is it’s probably the felt-pad of those tapes that should be replaced but I’m really not sure. I always carefully stored my cassettes.

All my other tapes (blank and pre-recorded) work fine so I’m 99 % sure that is not the fault of my recorder.

If you have some ideas or fixes to play them fine again, it would be great!

Nice day to everyone!

AUGUSTUS.