Oh the cause it not a leak or anything - it was a chunk of snow that made it in the trunk and then the car was in the garage for weeks - the cold weather - the sealed trunk - it got stinky..
Even after I wiped up all the excess water - I had to leave the trunk open for 24 hours to get it to completly dry. And I have found a really good natural odor/fungus/mildew killer etc...
Two teaspoons of tea tree oil mixed with two cups of water in a spray bottle - I just sprayed the trunk. (Tea Tree Oil has a strong smell but it dissapates in a day or so) - if you don't want the smell at all you can use grapeseed oil extract (about 20 drops in 2 cups of water.)
Thanks for all the advice ! (I was going to try cake PB
but the slice would never make it to the car!)