A method for reducing the negative consequences of sticky contaminants in the processing of waste paper, which comprises the steps of, when processing waste paper, adding an aqueous polymer dispersion comprising (i) a polymer A and (ii) a polymer B for coagulating and detackifying the sticky contaminants,
- (i) polymer A selected from the group consisting of a homopolymer or copolymer of acrylic acid or alkyl esters of acrylic acid, methacrylic acid or its alkyl esters, styrene, methylstyrene, vinyl acetate, itaconic acid, glycidyl methacrylate, 2-hydroxyalkyl(meth)acrylate, methacrylamide, N-hydroxyethyl(meth)acrylamide, dimethacrylate monomers, 1,3-butylene glycol dimethacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, propylene glycol dimethacrylate, dipropylene glycol dimethacrylate, 4-methyl-1,4-pentanediol dimethacrylate, divinylbenzene, trivinylbenzene and mixtures thereof, and
- (ii) polymer B comprises a styrene copolymer of acrylic acid, maleimide, maleic anhydride or mixtures thereof.