Is there an easy way to store unused paint for future use?

Store in a cool place and mark the can of which room it was marked for. Will not last forever .

I heard it was best to turn the can upside down to store. Any thoughts?

I store my paints in Mason jars. I use the larger ones when needed. I suppose if it's almost a full gallon, that would be impossible, though. I mark mine with what the paint was used for and always take a picture of the top of the can should I need more. Otherwise, storing it as Janet suggested would be correct.

I also use wide mouth mason jars for extra paint and keep a photo of the formula. You can buy empty quart size paint tins for storing extra paint. I find that using the original gallon paint can for storing less than half of a gallon not so great.