Place pooled extracts in dialysis sac. Immerse sac in 30% (w/v) PEG at 5°C until volume is reduced to 15-20 ml or less
(usually overnight). Remove sac from PEG and wash outside thoroughly with cold tap water to remove any PEG adhering to
sac. Soak in distilled water for 1-2 min and in 0.2 M NaCl for a few min. Pour contents into small beaker.
Rinse inside of sac with 2-3 ml 0.2 M NaCl by running fingers up and down outside of sac to remove material adhering to
sides of tubing. Repeat rinsing until rinse is clear. Keep volume as small as possible.