If by "Box" you mean the usual ones made of cardboard, storing your guns in them might be bad in itself.
Cardboard attracts moisture.
Collectors may cringe, but living in an area of very high humidity, I toss them.
Cardboard around here not only attracts moisture, but all kinds of bugs unless it's sealed with clear coat or the boxes with your guns are put in ziplock bags.
Cheap and effective, especially if the guns themselves are wrapped in silicone cloth.
If you want to use ammo cans, be sure they have seals for the lid.
If they don't, you can make them with suitably sized rubber tubing slit and glued into place.