PROBLEM TO BE SOLVED: To provide an agent for removing contraries from a flotator in a process for deinking waste paper, by which the contraries such as pitches, ashes and inks can effectively be removed from the flotator to give the deinked pulp having an excellent quality in a high yield in a state scarcely consuming an alkali, and to provide a method for removing the contraries. SOLUTION: This agent for removing the contraries from the flotator in the process for deinking the waste paper, characterized by containing a water-soluble amphoteric acrylamide-based polymer having a weight-average mol.wt. of 500,000 to 5,000,000, and the method for removing the contraries, characterized by adding a water-soluble amphoteric acryl amide-based polymer having a weight-average mol.wt. of 500,000 to 5,000,000 and comprising 0.5 to 50 mol.% of the quaternized methyl chloride or benzyl chloride units of dimethylaminoethyl (meth)acrylate, 0.2 to 10 mol.% of carboxylic acid-containing monomer units, 40 to 99.3 mol.% of acrylamide units and 0 to 2 mol.% of multi- functional monomer units into the flotator in the process for deinking the waste paper or to a process before the deinking process.
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