There are a few things you can do to clean a charcoal filter. The first is to remove all of the ash. This can be done by using a vacuum cleaner with the hose attachment, or by using a bucket and suction. The second is to clean the filter media. This can be done by using a soft cloth, or by using a vacuum cleaner with the hose attachment. Finally, you can clean the filters themselves by using soap and water, or by using an alcohol-based cleaner.