My first thought is this: Be very careful about using any cleaner which you would not want in your mouth. Things like water, diet coke, alcohol (i.e., vodka, grain alcohol - which I wouldn't drink straight, but diluted, ok - not rubbing alcohol, methanol, etc.), vinegar (ditto), mouthwash.
If you're going to use something that doesn't meet the "in my mouth" test then at least give the atty a post-wash bath to let the toxins dilute. Looking at the label of the Heat n Kleen, it's supposed to be mixible in water, so I'd at minimum give it a pure (well, tap) water bath after the HnK treatment - maybe two - before I'd consider using it.
That point aside: as long as your atty is not connected to a power source, there is no electricity going through it, and therefore there will be no electrical short circuits. Just make sure you dry it out before using it again, and you'll be fine. I've heard 24 hours recommended, that seems doable. You won't short your atty out, as long as it's dry before you plug it into a battery.