Personal Laserwriter - Help!

[Shadowrunner <Mario.E.Krismer@uibk.ac.at>]

hi everybody,

I got an old (1991) apple personal laserwriter ls for free. The reason
why is very simple: 

1) printing shows a gray-margin on the paper from the cardrige. Somebody
told me that after some time this can be 	caused by dust on the optical
parts. 
Can anybody tell me how I can fix it by myself?

2) I don't know why but printing one page needs 8 minutes!! on this
printer. What are possible causes?

Thanks very much in advance..

mario k.