HL-4070CDW FAQs & Troubleshooting HL-4070CDW Not your product? Sort by: Updated Date Popularity 3 Results 1. 01/27/2014 How can I clean the corona wire of the drum unit? 2. 01/22/2009 How do I clean the Drum Unit? 3. 08/31/2007 How can I clean the inside of the printer? Cleaning FAQs & Troubleshooting