Consult Your Manual

• Your owner's manual will be an important source of information when it comes time to check and clean your microwave's charcoal filter. The manual that came with your microwave should provide you with the recommended frequency for changing the filter, as well as tips on how to check the filter and clean it if necessary. The location of the charcoal filter will vary from model to model, so it is also important to consult the manual for the exact. location. In most cases, the charcoal filter will be in the overhead hood.
  
  

Remove the Vent Plate

• Unplug the microwave and locate the vent place covering the filter. The vent plate is typically held in place with two or three screws. Carefully remove those screws and set them aside in a film canister, ice cube tray or ashtray. This will ensure that the screws will be available when you need them. After the screws are removed, the vent plate should simply snap out, and you will have access to the charcoal filter.
  
  

Check the Filter

• Examine the charcoal filter's condition and determine whether or not it can be adequately cleaned. Most microwave manufacturers recommend that charcoal filters be replaced twice a year in order to keep odors to a minimum and keep the over running properly, so if it has been more than half a year, you may simply want to replace the filter. If you think the filter can be cleaned, you can use compressed air to remove any accumulated dust and debris, then carefully replace the filter and the vent plate.