You should go to your doctor and find out what is causing it.

Use a Q-tip and some rubbing alcohol to clean out your naval every once in awhile.

I also think that you need to just clean out your belly button it is a hole and like anything else stuff gets stuck in it you can use alcohol i always lay dwon and pour a little bit of baby oil in there let it sit for about a minute then use a qtip to clean it and then alcohol to make it extra clean!!