A sanitizing formulation comprising a solution of an acidic polymer and an anionic surfactant in a liquid vehicle. Suitable acidic polymers are those which include adjacent —[—CR1.COOH—]— units where R1 is defined in their structure, for example polymers based on maleic acid moieties which typically include —[—CH.COOH—CH.COOH—]— units, such as known Gantrez™ polymers. A suitable anionic surfact is sodium lauryl sulphate.