Thanks for the find. One concern I have is that at least with the zip lock bag, it definitely feels "less smooth", even after a very short period of contact. Whether it is 5 seconds or 30 minutes, the part of the ziplock that was touched by the EA feels less smooth than the other parts. I have tenatively washed a gallon ziplock back with EA such that all the smoothness was removed, and I am now using the gallon ziplock as my separatory funnel.

I'm evaporating it now and will check for residue.

BTW Loveall, I did a brine wash just now, and found that the weight of the brine did not increase. I.e., my H2O + NaCl mix originally weighed about 200g, and after mixing with my used EA for 5+ minutes on a stir plate, I separated the brine water from the EA via my ziplock bag, and it still weighed 200g. I would have thought that the brine would pull something out of the EA. Or at least pull out some water that was in the EA.

Does this mean my brine wash was ineffective?

I then dried with anhydrous magnesium sulphate, and was suprised to see that my magnesium sulphate turned green/yellow. After filtering the EA off, the magnesium sulphate had a strong EA smell. I then weighed my EA and found that I lost 50g of EA out of 460g EA.

It seems like drying with anhydrous magnesium sulphate resulted in a significant loss of EA.