I’ve found, in dealing with these things through the years, that if you don’t agitate spray cans regularly – when you go to use them, you’re not gonna get anything out.
The pigments settle to the bottom of the can, and when you hit the nozzle they’ll instantly load up the pickup tube.
You can store the cans upside down, which helps, or you can set up a schedule to agitate them. I rattle them up a couple of times a month, trying to make sure the pigments get into the solution. That ball has got to be rolling around in there for at least a couple of minutes before you’ll get good results.
So, there’s your FYI for now.