I'm sure it's happened to every 4WDer with a fridge at some stage. You open the lid only to be greeted with a smell that is strong enough to make the hairs on the back of your neck stand up. Of course if you clean your 12v fridge out each time you use it, you won’t have any dramas whatsoever and your fridge will constantly smell like roses. I know for a fact that this won’t happen and if you're anything like me you'll forget to clean your fridge more times than not. Because I travel around the country in my 4WD for a living and often leave it parked up for a few weeks at a time, sometimes in the tropial sun, you can only imagine the bad smells that often greet me when I get back into my vehicle.
One time I did the cardinal sin, leave the vehicle with a fridge full of groceries for a month. I won't go into details but there was sausages floating around in melted butter and milk that had cyrstalised. When I opened the fridge there was nothing except for heat that radiated from the fridge... then came the smell. It was so bad that most people would have thrown the fridge out just on principle, when they saw and smelt that sight. But you can make your fridge smell good again, no matter how bad the state. Most of the time just cleaning your fridge out won’t fix the problem as it will still smell rancid whenever you open the lid. I actually get asked all the time about by readers, 'how do I get the bad smell out of my 12v fridge?'
Well, I'm about to share a little tip with you that will change the way you camp that I've learnt from years of dry retching. Now days I will carry a small bottle of vanilla essence with me in my camping gear. As soon as I've cleaned the fridge out I drench a piece of paper towel in the stuff and leave it in the bottom of my empty Waeco. Vanilla actually appsorbs bad smells and of course, leaves everything smelling like vanilla. In my opinion it really is the best way to leave your fridge once the power is turned off. Another method is to cut an onion in half and leave that in your fridge for a day or so. The onion also is able to absorb smell, but you won’t want to leave it in the fridge for long periods as it will rot and then undo all your efforts.
Best of luck, and happy smelling.