Reasons: 1. Inverse the aerosol can during spraying; 2. Aerosol can body incline more than 45°during spraying; 3. Storage too long and exceed the Guarantee period. 4. The curving direction of the valve tube on the contrary. How to use: 1. Avoid inverse the aerosol can during spraying; 2. Avoid incline can body more the 45°; 3. Attention the Guarantee period; 4. When the remaining paint is around 20%, and feel the thickness is not enough (spray out mostly propellant), turn the valve nozzle 180° and use it again.