Best not to use any toxic cleaners on atomizers. If any traces are left, you'll be inhaling them.
Plain old hot water can remove thickened
e-liquid and sometimes helps performance especially if the atty had been clogged. Some people soak them, other hold them with tongs or pliers and run hot tap water through them.
"Dry-burning", which is heating the atomizer (without the cartridge on) until it glows for several seconds, letting it cool for a minute, then repeating, can sometimes help. It's good to do a hot water rinse afterward.
Atomizers won't work right with water left inside, so blow them out and stand them on end to drain. If you're in a hurry to use it, stand it on its threaded end and drip about 10 drops of
e-liquid in. Let it stand for a few minutes so that the liquid combines with the water, then blow it out. Put in a couple more drops of liquid then use it.