This is why God gave you a belly button. :rascal:
Or you could have one of those waterproof plastic pendants that used to be so popular for keeping keys and money in when you went swimming or to the beach.... I should think there is still an out of season tourist shop somewhere in nequay selling them to this day.
... the more adventurous amongst you may prefer to keep this torpedo shaped object somewhere damp and dark rather than swinging from your neck (as this location rather reduces ones street credibility.