You don't have to throw away that empty spray paint can that worked perfectly. Instead, you can refill the paint can by transferring paint from another can of paint. Also, if you have ever wanted to mix two paints to create your own personal colours, transferring paint from two spray paint cans can help you achieve your new mixture. Although it can be a little messy, refilling spray paint cans is a quick process.
Put the empty spray paint can into a freezer and let it sit for at least an hour. While the paint can chills, remove the top valves from two cans of Gumout Carb + Choke Cleaner, which can be found at any hardware or big-box store. Although the valves are the only things needed from the carburettor cleaner, you can still reattach them and use the cleaner for other purposes. Make sure that your can of cleaner comes with a small, thin spray straw, as it will be needed to transfer the paint. The valves should come off by simply pulling with a small amount of force.
Remove the spray paint can from the freezer when it is completely frozen and place one of the cleaner valves on top of the frozen spray paint can. You will see that it fits perfectly. Insert the spray straw into the side of the valve. Place the other cleaner valve onto the top of the room temperature spray paint can and insert the other side of the spray straw into the side of the valve. The two spray paint cans should now be facing each other with the straw in between, connecting the two.
Push down on the tops of both valves at the same time, as if you were spraying paint with both cans. The paint from the warm can will flow quite smoothly into the frozen can. Continue until all the paint from the warm can has been transferred. If the paint does not move quickly into the cold can, your spray paint can may not be frozen enough and you should start over.
Remove the valves from the tops of the cans and wash them with warm water and soap before the paint drys. You can use both the straw and the valves again when you wish to refill another spray paint can.
Work as quickly as possible to ensure that the frozen spray paint can stays as cold as possible throughout the entire process.
There may be some back-spray from the paint as you are refilling your paint can, especially if the spray paint can is not cold enough. You can help protect yourself and the surface you're working on by wearing gloves and having newspapers spread out when refilling the can.