The housings are not sealed. At least not on the older Aura H2O models. That model's water proofing achieved by a coating on the PCB. I googled this in a panic when a significant amount of water came flowing from the USB port as I removed it from the bath.

The "glue" he is mentioning on contacts probably isn't glue at all. There is no reason for glue to be there. Most likely, it was a waterproof coating.