The present invention provides a method for removing excess amounts of water-soluble amines from a diluted crude Mannich condensation product containing about 40 to 80 weight percent crude Mannich condensation product in an inert solvent which comprises: a) filtering the diluted crude Mannich condensation product in the presence of magnesium silicate and water, and in the further presence of a filter aid when the particle size distribution of the magnesium silicate is such that the average particle size is below about 50 microns; and b) recovering a filtrate containing a Mannich condensation product having less than about 0.05 mEq/g of water-soluble amine.