Filters used in the food and beverage industry can be cleaned by contacting the filters with a cyclic nitroxyl compound and a reoxidator or with a nitroxonium compound in a bromine-free process. The nitroxyl can be TEMPO or its 4-acetamido or 4-acetoxy derivative, and the nitroxonium compound can be the corresponding oxidized ion obtained by enzymatic or metal catalyzed oxidation. The reoxidator may be a peracid, such as peracetic acid, persulphuric acid or permanganic acid, or a metal complex with a hydroperoxide.