Just give it a light rub back with 12 then 15 then a light ghost of red then build up patience is your friend here.
Here is my tip for the day, shake the can up well,then put it a mug with boiling water in it for 20 seconds,take it out shake well again then ad can back in the water for another 20 secs,No longer you don't want the top blowing off now do you this will heat the paint inside the can and will spray loads better