Slowakische Kassettensite mit allen Einlegern

[EZ647]

I remember seeing those Basf with that type of case, I think I've seen Realistic ones like that too.

An interesting problem is on the Fuji Video8 Japan, almost all Fuji Japan video cassettes of this type have the dust cover covered with a crystalline structure on the inside and outside, this damages the tape a lot.
The tape only has this structure in the part as it is pulled off the spool, the rest seems to be fine.
Could it be some special type of plastic?
I won't be able to get a photo today, but I'll add one tomorrow.

Regards EZ