This brochure has good info. on what blow by gases consist of and different ways of filtering cranckase gases. It is for Racor closed crankcase ventilation systems.
http://www.gemo-online.de/pdf/Industrie/eng/CCV-Brochure_eng.pdf
http://www.gemo-online.de/pdf/Industrie/eng/CCV-Brochure_eng.pdf