Hi everyone. I've got an issue with the Tamiya Spray Primer can I've just finished using. I've been spraying it upside down to clean it for ages but grey just keeps coming out of it. Am I doing it wrong, or is the propellant grey too?

Any help would be greatly apreciated!

I have never seen gray propellant, and I have used countless formulations in spray cans. I'm not sure what you mean by "ages", I would think that after spraying that long there would be no propellant left I think what the issue in your case is that the heavier particles have accumulated around the outer ring on the bottom and on the sides and are slowly working their way free. What you need to do is spend a few minutes (or maybe a lot) rolling the ball around the outer ring on the bottom of the can, and then slowly work the ball along the side of the can until the can is upside down where you will need to roll the ball around the top (which is now facing down) for a little bit more. This will help knock the rest of the heavy deposits off so that you can eject them out of the can when you are cleaning it out.