A few weeks ago, my granddaughter dropped a open milk drink with a straw in my car. It rolled under the passenger seat and I told her don’t worry, that I will get it when we get home. Well, you won’t believe it, but I forgot all about the drink and it sat under the seat for a few weeks. 
I take mass transit to work, so the only time I drive is to go visit. As soon as I got into my car – wham – the stink hit me, but I forgot about the milk and drove all the way to my daughters, thinking, I have to throw out my shoes, because it smelled like a dump in the car. (I didn’t know what else to think as I was driving). When my daughter got into the car she said, Mom , what is that smell? I said it’s my shoes, then she gave me the mommy look and started to look around the car and she found the container with the rotten milk. 
She went into the house and got the baking soda and sprinkled it on the floor mats in the back. It worked, after shopping for a couple of hours, by the time we got back into the car, the odor was pretty much gone. I was very happy beacause I really liked my shoes 🙂
Home Digest has 4 more ways to get out car odors :
Sniff Salts: Pour fragrant bath salts into a loose-leaf tea strainer, and place it in the glove compartment for a fast refesher every time you pull out the map.
Get a whiff of wax: Drop a potpourri wax candle tart into a cup holder and take your favorite scent with you wherever you go.
Dry and drive: Lay fresh herbs, like basil, on a piece of newspaper in the backseat and leave the windows rolled up to dry the leaves, and banish bad odors.
Sprinkle oil: Shake a few drops of lemon or eucalyptus essential oil onto car mats for a naturally sweet scent that will last a few weeks.
Hope you find these tips helpful, and keep your shoes!