A slow cooker does exactly what it sounds like. It allows you to cook foods like roasts, rice and stews slowly over the course of an entire day, a task that not only leaves you with well-marinated and tender dishes, but that saves you from cooking an entire meal after you've gotten home from a long day of work. However, since food items are in the appliance for so long, the slow cookers can often take on their smells. For example, most slow cookers come with lids that have a rubber seal, and the rubber can absorb the smell of the food. Luckily, you can easily fix that.
Fill a basin with undiluted distilled white vinegar until the basin has around 3 inches of vinegar in it. Add 1 tablespoon mild detergent. Swish the two substances around with a spoon until you have some soapy bubbles.
Place the lid of the slow cooker into the mixture so that the rubber seal is face down and completely immersed in the vinegar and soap solution. Allow it to soak for at least one hour, but ideally two.
Rinse off the vinegar and soap with cold water. The smell will be completely gone. Pat dry with a clean towel.