CPV code 90919300 designates School cleaning services in the Common Procurement Vocabulary (CPV 2008), the EU classification used to describe the subject of public contracts.
90919300 is a leaf code — the most specific level of its branch — so it can be used directly as the main CPV code of a contract notice. If it does not quite fit, check the neighbouring codes under 90919000 (Office, school and office equipment cleaning services).