Use of a compound, in a process for extruding polypropylene comprising, in order, the steps of (a) forming a first extrudate by extruding a first composition comprising a first polypropylene, a first acid scavenger, and ≥ 50 ppm of a nucleating agent which is selected from phosphate ester salts, sodium benzoate, lithium benzoate, bis(4-tert-butylbenzoate) aluminum hydroxide, talc, and compounds of formula or; (b) forming a second extrudate by extruding a second composition in the same extrusion system as the first composition, the second composition comprising a second polypropylene and the compound, wherein the second extrudate contains < 10 ppm of the nucleating agent; wherein the compound is selected from (i) a metal salt of a fatty acid comprising a cation of a metal selected from Li, Na, K and Mg if the nucleating agent conforms to the structure of formula: wherein M 1 is an organic or inorganic cation, x is 1 or 2, y is 1 or 2, R 1 -R 10 each independently are H, OH, C 1 - 9 -alkyl, C 1 - 9 -alkoxy, C 1 - 9 -alkyleneoxy, amine, C 1 - 9 -alkylamine, halogen, or phenyl, wherein any two vicinal or geminal alkyl groups may be combined to form a carbocyclic ring of up to six carbon atoms, and wherein the carboxyl moieties of Formula are present in cis configuration; (ii) metal stearoyl-2-lactylate, wollastonite (CaSiO 3), silica, and magnesium oxysulfate, and a metal salt of a fatty acid comprising a cation of a metal selected from Al, Mn, Zn, K and Mg if the nucleating agent conforms to the structure of formula: wherein M 11 and M 12 are each independently selected from metal or organic cations, or are combined to form a single moiety, and R 20 -R 29 each independently are H, OH, C 1 - 9 -alkyl, C 1 - 9 -alkoxy, C 1 - 9 -alkyleneoxy, amine, C 1 - 9 -alkylamine, halogen, phenyl, alkylphenyl, or geminal or vicinal C 1 - 9 -carbocyclic; and (iii) a metal salt of a fatty acid comprising a cation of a metal selected from Na, Al and K, if the nucleating agent is selected from phosphate ester salts, sodium benzoate, lithium benzoate, bis(4-tert-butyl-benzoate) aluminum hydroxide, and talc; as a second acid scavenger for deactivating residual amounts of nucleating agent in the second extrudate. (a) forming a first extrudate by extruding a first composition comprising a first polypropylene, a first acid scavenger, and ≥ 50 ppm of a nucleating agent which is selected from phosphate ester salts, sodium benzoate, lithium benzoate, bis(4-tert-butylbenzoate) aluminum hydroxide, talc, and compounds of formula or; (b) forming a second extrudate by extruding a second composition in the same extrusion system as the first composition, the second composition comprising a second polypropylene and the compound, wherein the second extrudate contains < 10 ppm of the nucleating agent; (i) a metal salt of a fatty acid comprising a cation of a metal selected from Li, Na, K and Mg if the nucleating agent conforms to the structure of formula: wherein M 1 is an organic or inorganic cation, x is 1 or 2, y is 1 or 2, R 1 -R 10 each independently are H, OH, C 1 - 9 -alkyl, C 1 - 9 -alkoxy, C 1 - 9 -alkyleneoxy, amine, C 1 - 9 -alkylamine, halogen, or phenyl, wherein any two vicinal or geminal alkyl groups may be combined to form a carbocyclic ring of up to six carbon atoms, and wherein the carboxyl moieties of Formula are present in cis configuration; wherein M 1 is an organic or inorganic cation, x is 1 or 2, y is 1 or 2, R 1 -R 10 each independently are H, OH, C 1 - 9 -alkyl, C 1 - 9 -alkoxy, C 1 - 9 -alkyleneoxy, amine, C 1 - 9 -alkylamine, halogen, or phenyl, wherein any two vicinal or geminal alkyl groups may be combined to form a carbocyclic ring of up to six carbon atoms, and wherein the carboxyl moieties of Formula are present in cis configuration; (ii) metal stearoyl-2-lactylate, wollastonite (CaSiO 3), silica, and magnesium oxysulfate, and a metal salt of a fatty acid comprising a cation of a metal selected from Al, Mn, Zn, K and Mg if the nucleating agent conforms to the structure of formula: wherein M 11 and M 12 are each independently selected from metal or organic cations, or are combined to form a single moiety, and R 20 -R 29 each independently are H, OH, C 1 - 9 -alkyl, C 1 - 9 -alkoxy, C 1 - 9 -alkyleneoxy, amine, C 1 - 9 -alkylamine, halogen, phenyl, alkylphenyl, or geminal or vicinal C 1 - 9 -carbocyclic; and (iii) a metal salt of a fatty acid comprising a cation of a metal selected from Na, Al and K, if the nucleating agent is selected from phosphate ester salts, sodium benzoate, lithium benzoate, bis(4-tert-butyl-benzoate) aluminum hydroxide, and talc;