I just noticed that lots of the cds I have in my car are quite badly scratched. Even new ones bought less than a week ago. I keep pretty good car of my cds, even my car ones and I always replace them carefully back into their cases, when I finish playing them. Is it possible, that the in-dash (BMW OEM) single slot loader CD I am using could be scratching them? I have always been suspicious of slot loading players.
A slot loader (be it a single or multiple one) leaves scratches on CDs. The CD is rubbed against some brushes to ensure it is clean before it enters the inside of the player. These brushes eventually scratch the CD.
The CD is generally not scratched by the player itself (once it is inserted).
Some slot players have problems reading certain types of discs (CDRW for example) and can scratch them, as they throw out the disc for a second and pull it in again.
When they pull it in again, the disc may be a little out of place (depends on the way the player is mounted!) and will get scratched by the mechanism.
One brand that’s known for this to happen is Aiwa.