Put the brakes on stopped-up nozzles
Makers of aerosol finishes typically suggest you clean a nozzle by tipping the can upside down and spraying. That wastes finish and propellant, and you may still end up with a clogged nozzle. Here's a better way I've used with success for years.
When you're done spraying, remove the nozzle and attach it to a can of brake parts cleaner (available at auto parts stores). Give a brief spray, wipe the tip of the nozzle with a rag, and replace the nozzle on its original can. That's it! You will likely need two cans of brake parts cleaner: one that accepts male-type nozzles and one that fits female-type nozzles. My aerosol cans never run out of propellant, and I have bags of leftover clean nozzles to share with friends who still clog them!
—Jim Jackson, Fruitport, Mich.