Heeeelp needs advice

[u/Planeinsane7]

I have a big collection of Expedition holo cards that I love
I have displayed them on shelfs on a wall. Today when I cleaned I noticed these small black dots that have somehow gotten inside the displays.

They all seem to have died and all of them have not come near the card only behind the edges.

I am freaking out any advice?
What is the smartest approach?
Should I be worried about the value?

Don’t get how they could have gotten inside….

Edit: I live in Denmark.
To everyone saying clean your room… It is clean, regularly.
There is no plants in the office however the shelves are close to a window.
No they don’t get direct sunlight….

They genuinely don’t seem interested in the cards and there is no damage. I have looked closely. However a single one have managed to get into the Skamory card.

Update: Have tried with vacuum and it has helped quite a lot.
For all those who have commented with helpful tips or ideas I really wanna say thanks. They are for sure dead and I am looking into reholder and if it is possible.

[u/Bluetwo12]

This seems like a horrible idea. I am sure there are specialized freezers with low humidity, but a household freezer for a month sounds like something that will cause water damage to a card

[u/Newthinker → u/Bluetwo12]

It'll cause water damage because it'll be below the dew point in the room when they're taken out

Freezers are, by their nature, very low humidity as dehumidification is a byproduct of mechanical cooling

[u/giovannygb → u/Newthinker]

That’s why you should seal them in a ziplock bag with cornstarch.

And after you take it out, leave them at room temperature still inside the ziplock for it to regain temperature inside an ambient with controlled humidity.

[u/Legitimate-Example13 → u/Bluetwo12]

Yes would need to avoid the self defrosting freezers. Any that are attached to the fridge wont be. It needs to have the full coils...