A method of preparing a composition, comprising (a) a micronised insoluble organic UV absorber, which method comprises grinding the insoluble organic UV absorber, in coarse particle form, in a grinding apparatus, in the presence of a grinding aid selected from the groups (b1) carboxylic acids and their salts; (b2) fatty acid esters (b3) alkyl phosphates or phosphoric acid esters; (b4) ethoxylated carboxylic acids or polyethyleneglycol (PEG) esters; (b5) fatty alcohol polyethyleneglycol (PEG) ethers of fatty alcohols; (b6) polyethylene/polypropylene -glycol ethers of saturated or unsaturated C4 - C28 fatty acids; (b7) ethoxylated alkylphenols or ethoxylated alkylphenyl ethers; (b8) esters of polyol and mono-, di- or tri-glycerides; (b9) esters of fatty acids and saccharose; (b10) sorbitan mono- and di-esters of saturated and/or unsaturated C6 - C22 fatty acids and ethylene oxide groups; and (b11) surfactants which are mainly acting as detergent or cleansing agents.