FORENSICALLY CLEAN MEDIA A forensically clean drive is one that can be proven to be devoid of any data at the time the clone is made. Being sterile is another way of looking at it. It is important to prove the drive is clean because comingled data is inadmissible data. Drives can be cleaned with the same devices used to make the clones. The cleaning process overwrites the entire hard drive with a particular pattern of data such as 1111111111111 (Casey, 2011).