I thought people with piercings UNDERSTOOD that ya have to remove your jewelry every day to clean the holes in your skin out...? Similarly, you should be cleaning your navel regularly. Think of it like they are the bellybuttons in your ears, lips, nose, privates, etc.! But -- shockingly (and scarily) enough, from things I've read, seen on television, etc., there are a lot of people who believe it is adequate cleansing to simply, very quickly, pass a sudsy loofah between their legs in the shower! What in the bloody hell?!? Sadly, they are immune to their own BO. Every crevice, piercing, etc., requires a thorough clean with a pretty strong body wash and your fingers, or in the case of piercings, a very slim tool. Waxed dental floss & a floss-threader are very effective, i hear.
I keep my earnings in for months at a time and have never had that issue. I do tend to wear gold or silver only. Maybe that has something to do with it too.
