Just a thought to throw out here, if your concerned with whatever dust might get into that very small opening, lay some cheesecloth or a tissue over the top. The liquids would still be able to breathe but still be protected. I personally don't cover anything but if you feel more secure, do the above.
Another thing, it's not necessary to put them in the dark, just keep them out of sunlight. Since I have no children or pets, unless you count my Hubby, mine steep on my kitchen counter next to my Vape Station. All lined up along the back wall. I have a long counter and they are quite some distance from the stove.