Before painting a room, combine the cans of the same color wall paint together in a larger bucket and stir thoroughly to eliminate any variations in color that might occur. There is actually a color variation between cans of paint even from the same manufacturer and the same color. Mix the paint thoroughly between each addition. Mix it using a paint stirrer. Mix from the bottom upward to ensure that the heavier pigments blend thoroughly with the lighter thinner. If the paint is too thick, add a small amount of paint thinner.
When mixing leftover paints to create your custom color, only mix the same “type” of paint together.You’ll find out when paints aren’t compatible (for example an oil and water-based) because if you try to mix them, you’ll end up with a lumpy mess.
Strain your paint. Experts recommend pouring the paint over a window screen to make sure there are not chips or other debris in your paint. It is best to tape the screen to your bucket. You definitely want to use this technique if you are using older paint, since you tend to get little chips of hardened paint that could ruin your new paint job. Sometimes a skin could also form on the top of your old paint. You will want to filter that stuff out so it does not end up on your wall.
Remember to wear protective gear including gloves, respirator masks and safety glasses when working with paint. If you need help, call the experts!