Method for reducing the concentration of isocyanates in streams

The method comprises the step of putting said streams contg. isocyanate(s) in contact with a soln. of at least one compd. selected from RCH2X(CH2R')​CH2(CH2)​nFg and R''CH2YCH2(CH2)​nFg (R,​R',​R'' = H, C1-​10 hydrocarbyl group optionally contg. heteroatoms; X = N, P, hydrocarbyl contg. N, P; Y = O, S, hydrocarbyl contg. O, S; Fg = primary or secondary amines, OH, SH, preferably Fg is selected from -​NH2 and -​NHR1, wherein R1 is C1-​6 alkyl group having; n = 1-​5, preferably 1-​2)​.