Marks on PSA Case?

I recently bought the most expensive card I’ve ever paid for.

However, on the back I noticed something that looks like grime?
I can’t tell if it’s on the card or the slab.



I’m hoping someone here who has seen something similar on their slabs.
And that’s it’s not on the card.

I see marks like that on slabs all the time, you can try dabbing a tiny amount of goo gone onto a paper towel and then scrubbing at it

tiny amount of goo gone

Thanks, gonna try this

The squares are normal, part of the case

As long as it’s not on the card, I can live with it. But I swear it looks like donut frosting on my card lol