how do I kill mold without destroying cardboard box

does anyone know how I can kill mold and clean up cardboard product boxes without destroying the boxes. I have in the past killed and controlled mold with boric acid powder dissolved in hot water . and white vinegar  but that was on wood and other stuff. I want to try and keep the printed stuff on these vintage package boxes.
I have boric acid powder, borax, vinegar and some peroxide-the kind you clean cuts with.

Peroxide is a bleaching agent, so I'd worry that might discolor the cardboard and printing you are trying to keep.

Maybe a soda blaster set on low could be used to gradually strip the layers?

There's some good information here for books, and I imagine the needs of cardboard would be the same: https://biblio.co.uk/book-collecting/care-preservation/prevent-remove-mold-mildew/

One trick I used to use when I collected old books was to seal larger books book up in an airtight plastic box with plain unscented clay cat litter for a couple of weeks, so the cat litter absorbed the moisture and odor. A larger scale version of the baking soda method mentioned in the article. Then once the mold was dry, it could be brushed off using a soft brush like a paintbrush or a blusher brush.

The problem with mold and paper products is that the mold will almost certainly recur if the items are exposed to damp or high humidity again. It's almost impossible to kill the spores on paper. Some sources say sealing the item in a plastic bag and freezing it will kill mold spores, but others say no. My experience was that freezing would kill the active mold so it could be brushed off, but the spores remained, meaning the mold might come back.

I wonder if UV light or something along those lines could be useful. Just spit-ballin'. I think the issue is eradication without harming the underlying media (paper based) with liquid chemicals. https://www.epa.gov/mold/does-ultraviolet-uv-radiation-uv-lamps-kill-mold  You might have to do more research, but, this was the first thought off the top of my head. Hope it helps.

Run an ionizer in a container or a room, depending on size of your inventory. Vacuum seal with FoodSaver right after if size allows. Though this won't do anything to visual residues.

I'm not sure about an ionizer, but an ozone generator could work - put it in a small sealed box to get a good concentration. Again, it won't get rid of staining, but I gather it can kill mould spores (along with houseplants, small animals and people....) Reference:mould advice company

To me, it seems like the easiest way to kill mold on a cardboard box would be to put the box in the oven at 250F for long enough to kill the mold.

The thing about mold is, not only do you have to kill it but you also have to store it somewhere that it can't get moist and support more mold. Or else it just starts over again. Concrobium mold spray is remarkably safe (I even use it on seed germination soil) but cardboard is tricky since treatment works on the surface and a lot of molds will be happily living down in the corrugations where you can't reach them without saturation which is likely to damage the cardboard even worse.

Since you've had success with boric acid and vinegar in the past, you might want to try a mild solution of those ingredients on a small test area of the boxes. Just be sure to use a gentle touch and avoid saturating the cardboard to prevent damage.

I also have put molded paper products out in the sun for them to become safe.

I might have just rinsed them with water.