Main reason:

1.Before spraying, the liquid is not fully shaken resulting in clogging the injector by sediments pigment.

2.Use too much power to shake resulting in broking down the ball which will clog the injector. 

3.After using it without cleaning spray injector by placing upside down for three seconds,it will cause clog by the remaining paint.

4.During the storage process, inverting or side cause the paint precipitate clog the valve.  

5.Over the shelf life of the product, its content will block up the injector.

Precaution:

1.Shake the can before spraying down about two minutes which get the best effect.

2.Using the correct way to shake the paint, not use too much power to break down the glass ball.

3.After spraying, it should be inverted the can about three seconds to clear the injector and then store.

4.When for storing, it should pay attention to not play upside down and side of the can.

Correction method:

Pick up the injector to paint upside down for three seconds to clean the valve and the replace the injector.