Store any leftover rub in an airtight container or jar for up to 6 months. Be careful to not contaminate your rub if you plan on storing it. Avoid touching raw meat then putting your hands in the rub. I recommend using a spice shaker to apply the rub to avoid this. Commercial rubs typically have anti-clumping additives bet this homemade version does not, so it may clump a bit in storage. Just give it a quick stir with a fork before use to break it up.