Coagulated SBR or nitrile rubber latexes with low salt contents, suitable for processing in belt or bar driers, are prepd. by adding mixts. of NaCl and quaternary ammonium polymers to the latexes. Thus, an 18%-solids nitrile rubber latex contg. 0.4 phr poly(dialkyldimethylammonium chloride) (I) requires 50 parts satd. NaCl soln. for complete coagulation of 100 parts latex, compared with 150 in the absence of I. [on SciFinder (R)]