Wait! It just hit me! Alright, after you use Displex to remove the scratches from your screen, you should definitely invest in a screen protector, or else your device will just end up scratched again. I recommend The Invisible Shield to you. I use it for my cell phone, all 3 of my PSPs, my Sony CyberShot...yeah, you get the idea. The material they use to make the their protectors is the same material the army uses to protect their helicopter blades. The shields come with a lifetime warranty so if it ever gets dirty, you can send it back to them and they will replace it for free.
What kind of mp3 player are you talking about anyway? If it happens to be the Meizu M6SL, here is a link to their shield made specifically to fit its screen:
ZAGG | invisibleSHIELD | Meizu M6SL Cases, Screen Protectors, Covers, Shields, Skins, Invisible Shield
If it's not the M6SL you're looking at, then you can use their search function to search for your device. They have a realllly wide selection (\(^o^)/)!