I don't know for sure, but it seems save enough for me. My concern would be whether they are sufficiently moisture resistant.

You mean 'mouse proof' as in they can't shimmy through the crack in the lid? Or mouse proof as in can they eat through the plastic and make a hole?

I've had mice in the garage make holes in the bottom corners of Rubbermaid trash bins that I use for storage of gardening supplies. I've also had mice squeeze in through the lid on non Rubbermaid brand totes even though it was snapped down tight.

Since you do not need to access the stored items continuously I would duct tape around the lid to be on the safe side. Mice do not seem to like to chew on the stickiness of duct tape. Sealing the totes with tape also prevents damage from flooding should it occur. Mice seem to like chewing at the corners of these things so maybe smearing the corners with tobasco or some other repellant will help.

Thanks - I never thought of duct tape!! Moisture isn't a problem. Time to get to work............

They are not mouse-proof or squirrel-proof.

Mice can get through incredibly small cracks, so since all those lids give a little, they can get in.

The lids aren't like Tupperware lids.

Duct tape will trap any moisture inside, bcs it's waterproof. You might get several of the moisture-absorbing desiccant packets (some people call them "do not eat's", which cracks me up). I think Michaels might sell them.

There's also an oxygen-absorbing pack, but that's probably overkill

They do make storage containers that have tight lids like Tupperware. I have some. I got them at ReStore, so I don't know the brand.

If you are looking for critter-proof containers get ones that are made of polycarbonate I think the code is *7*. Mice won't chew through the thick hard, brittle plastic, like they do the softer plastics. One neat-o thing about PC containers is that they are see through and you can find stuff easier. Of course you will pay a lot for polycarbonate containers.

Check out using steel shipping containers. They are mouse-proof with tight lids but the round shape may make them cumbersome for storing papers.

Here is a link that might be useful: Rubbermaid Mouse Proof