Claim: Sunshine Cleaning is named after its main character's crime scene cleanup(a term applied to forensic cleanup of blood, bodily fluids, and other potentially infectious materials) business in which they first struggled with.
Evidence: Mac recommends a crime scene cleanup job, and with his connections as a police officer, he gets Rose and Norah into the business. The sisters name their cleanup business "Sunshine Cleaning" and start making progress as their reputation grows. Crime scene cleanup is a term applied to forensic cleanup of blood, bodily fluids, and other potentially infectious materials (OPIM). At first, the sisters are unaware how to perform their job properly, carelessly handling the hazardous materials by throwing them into dumpsters instead of becoming licensed and properly disposing of bio-waste in an incinerator.