Frankie:

On that orange match safe, before you give up on it, there may be a cheap fix.

If the "O" ring is at the bottom of the threading so that it seals when the screw on cap butts against it, get a slightly thicker "O" ring with the same inside diameter. This will allow the new "O" ring to fit over the throat of the match safe, and the thicker "O" ring will contact the cap sooner and effect a better seal.

The other method is if the "O" ring fits on a groove on the throat of the match safe. You can buy a bigger inside diameter "O" ring that will seal by the cap butting against it, or you can wrap teflon plumbing tape sealer around the upper part of the "O" ring so that the cap squishs the teflon tape onto the "O" ring as you screw the cap down. With the teflon tape method, you will have to redo the tape every time you open the match case.

Easiest method is to wrap the match safe in plastic sandwich wrap. If you are under water (Assuming you have the match safe on your person.) long enough for the water to work its way through the Saran wrap, you will probably need a priest and not dry matches.

You can buy "O" rings of different thicknesses and diameters in Auto supply houses, hardware stores, and bearing supply houses.

Good luck!

Bountyhunter