I used to boil attys as part of a bi-weekly, thorough-cleaning routine, and it never seemed to cause any problems.
Then I decided that I had better things to do than to waste time getting all OCD about the cleanliness of my atomizers. Now, I'll use one for a week, blow it out, rinse it, and drop it into an alcohol bath for a ½ hour. Then it sits on the shelf for a week drying out and waiting to come back around in my atomizer rotation.
Hmm, OK... It may sound like I'm still all OCD about it, (and perhaps I am

), but the time I spend cleaning them this way is a fraction of what it was before.