third year one of the things i realized is this. Lets say the odor is coming from your feet then what you should do is smell your feet and socks to see if they stink and give out that odor. If they don't then it's not your feet. The same to other parts of your body. Smell your underarms or rub them in with a clean towel and then smell the towel to see if you can get that same odor onto it if not then its not external and possibly originating from your mouth or nose.
As for me my feet would never stink. If I used a foot powder at the end of the day when I smell them it smells like the foot powder. I told my mom about this and she thought I was crazy she was like your socks/sneakers don't even stink. My underarms would not stink like that. If i sweat i give out a Body Odor that I am accustomed to. To get rid of that one all i had to do was take a shower but the other one (moldy/dirty mop smell) would just linger no matter what i tried.