Cleaning compositions including a photocatalytic material and a sensitiser employ a photocatalytic material and a sensitiser at a locus, for example on a surface. The residue combats soils and/or undesired microorganisms at the locus. The photocatalytic material is peroxo modified titania, preferably in its anatase form, or peroxo modified titanic acid, or a mixture thereof. The compositions are preferably alkaline.