It all seems to wipe off and I've had no issues with stuff playing in it, I just want to be a little proactive before it gets worse.

I looked at a few movies I watched around Christmas time and they look all fine on the bottom, and it looks like it stated with the strange smudges around two weeks ago. Like I said it's weird because it just started doing this. You could be right about the rubber shield thing. I very rarely play discs that aren't my own, and when I do I look them over first and if they're dirty looking I'll clean them off with a microfiber cloth. One thing you never want to use with any Blu-ray drive is a cleaning disc with a brush attached to the surface, not that that would help with cleaning the rubber dirt guard. I think there are tutorials on youtube for opening the device and doing a more thorough job, at least for the PS3, assuming your warranty has already expired. I haven't had cause to see if the PS4 works the same way. With the PS3 you could clean it with a q-tip dipped in rubbing alcohol, just don't make it dripping wet or stick it too far in the machine. If it gets a fine particle of dirt in it, the next thing you know your discs might be coming out scratched too. The rubber shield designed to catch dirt, skin oil, popcorn butter, etc to help keep it from gumming up the laser, just traps it and it builds up over time. Do you watch or play rental discs much? That's my biggest pet peeve with slot loaders - they're harder to clean, almost as if they're preying on people who don't know to always clean their discs, which these days sometimes even need cleaning from the factory.

Ps4 disc drive cleaner