Preserving stains and varnishes just makes sense. You'll save money, be able to match new projects to existing ones, and make hard-to-detect repairs to dings and nicks.
Spraying into can

Keeping finish fresh requires limiting the liquid's contact with oxygen and storing it at a finish-friendly temperature. Oxygen causes finish to cure; temperature extremes break it down.

Reducing or eliminating oxygen in the container starts when you open the can. To pry up the lid, use a paint-can opener, not a screwdriver or, heaven forbid, a chisel. Using the right tool prevents damaging the lip on the lid or the groove in the can, preserving an airtight fit.

Pour a small amount of finish into another container and reseal the original can while you apply stain from the smaller container. When reinstalling the lid, tap it in place with a rubber mallet to prevent deforming the lid or the can. Such damage makes a tight seal impossible.

Marbles force out the air

After applying the last coat of stain or finish, use one or more of the following tips to minimize the amount of oxygen in the container before storing it:

* If you haven't used much of the finish, add a few marbles to displace air in the can (photo below). But don't add more than you can easily fish out, as you'll need to stir the finish before using it again. Using larger marbles means fewer to retrieve later.

Putting marbles in a jar
Carefully drop in a few marbles to raise thelevel of the finish. Glass marbles won't reactwith the finish, and wipe off easily for reuse.

Reduce the finish's surface area

* For cans with 112 " or more of air space, transfer the finish to smaller containers (photo below). Oxygen can permeate plastic, so stick with glass jars or metal cans with tight-fitting lids. Narrow containers expose less finish-surface area, further reducing the amount of finish in contact with air. Clear jars allow you to inspect the finish to see if it's good without removing the lid. Regardless of the container, wipe the rim clean before adding the lid for a tight seal, and attach a label with the finish information and date you stored it.

2 jars and a can
Use the smallest container possiblefor storage. The wide jar, left,exposes more than twice the surfacearea of the finish compared with the small jar.

Add Bloxygen and store

* Bloxygen (photo below; Source: Bloxygen, 888-810-8311,, a can of compressed argon gas (which is heavier than oxygen), provides another solution. Direct a 2-second burst of Bloxygen into the can and the argon settles on top of the finish, displacing the air and preventing it from contacting the finish.

Spraying into can

After sealing the container, find a suitable spot to store it, ideally from 50 degrees F to 70 degrees F. For water-base finishes, avoid any location that drops below freezing. And keep both oil- and water-base finishes away from any area that reaches 100 degrees F or higher.