Always pour paint out of the can over the front of the label; pouring over the back may obliterate the directions, and you may need them down the road. Alternatively, remove and file away the label and mark the can lid with a Sharpie pen so you know what it is. If you obliterate the directions, marine paint companies such as Interlux have detailed user guides for their products online.
20. Balloon Trick
Half-used cans of paint will last longer and stay fresh if there’s no air in the can with the paint. Commercial vacuum products, like the Pump-n-Seal ($32.95, pump-n-seal.com) are available. Other guys open the valve on a propane torch above the can before resealing to displace oxygen. a simple solution that works for up to a year is to place an inflated balloon atop the half-filled contents of the can to displace the air before re-lidding.