This is a bad idea. The wooden comb will swell when wet. In theory this may make it more airtight. But when it dries, the wood will crack and leak even worse. Plus your instrument will start to rust.
Moisture (including saliva) is the thing that is not good for harmonicas.
Keep it simple. Have a clean mouth - so nothing gets into your harmonica; Clean hands - as you are putting the instrument in your mouth. When done playing, you can wipe down the cover plates and let it air dry.
You do not really need to do much more than that.
The sonic cleaners work also, but again, you need to carefully dry all the parts and reassemble, without bending reeds etc whilst handling the instrument with cover plates off.
The soaking idea is a myth. No professional does it except for show.
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