Hi Tiny,
I look after a large firearm collection in a museum, mostly early breech and muzzle loading weapons. You might find that the humidity is very high in the room that you keep the weapons in. It should be about 30% to 40% and constant. Apart from the anti rust agent cloths you can put in the cabinet which is a cheap option, you may want to consider buying a small dehumidifier to plug into the room. This may sound drastic and expensive, but they are about £150 approx to buy from Comets, Currys etc, and you will be suprised how much moisture they draw out of the air.
As we keep about 1500 firearms and cutting weapons, it is essential to check the humidity. The reserve firearms collection is kept under the museum in a bunker, which does give humidity problems. I have overcome the problem of rusting by using a combination of a small electric heater, and xpelair fan on a timer, and a dehumidifier. We have no problems.
If you are storing weapons for a long time, you can purchase a wax called microcrystaline wax, once applied to metal it cuts the air off and providing the seal is not broken it does preserve the metal quite well from rust spots.
Hope the above is of some use to you.