Humidity doesn't cause tarnishing, it excelerates it.
Since World War II, silica gel has been the drying agent of choice by government and industry. It is safe to use with even the most sensitive materials, including food and medicine—it’s what is contained in those tiny packets enclosed in pill bottles and shoe boxes to prevent moisture. It prevents tarnish- and corrosion-causing condensation within enclosed areas, such as flatware drawers and china cabinets. Such areas should be made as vapor-proof as possible.
Despite its name, silica gel is not a gel, but is in the form of chemically inert man-made granules containing thousands of tiny crevices that “drink up” excess humidity from the air by surface adsorption. A good choice of product is a canister containing silica gel that turns from blue to pink when saturated with moisture. Reactivate the gel by drying the canister in a conventional oven. The reactivation process can be repeated indefinitely for a lifetime of protection.