Those Plastic Blue Note Innersleeves
![LaserWolf](https://community.soulstrut.com/uploads/useravat/n148.jpg)
You know, late 70s innersleeve with plastic liner. Those things discolor the vinyl. Occasional the discolor can be lightened with cleaning, but usually not. I have not noticed it effecting sound, but sure is ugly. I hate plastic sleeves. If you got a piece of grit in there the plastic sleeve will rub it against the record.