Many kitchen exhaust hoods have a charcoal filter that naturally absorb odors. These filters are disposable and should be replaced over time. But did you know you can also reactivate the charcoal filter and reuse it a few more times? When the filter is full of absorbed odors and residual grease and smoke, simply give it a good wash with dish soap in the sink. Place it in a preheated oven set at 200 degrees, and let it dry out for 10 to 15 minutes. Turn off the oven and let the charcoal sit. This reactivates the cleaned charcoal and lets you reuse the filter one more time.