The glass itself should be ok, but the metal ring and silicone lined top is of concern. The metal is supposedly stainless steel. I have to creatively fix 100um embryos for SEM and it is not feasible to pipette transfer through the fixation in microcentrofuge tubes (shear force destruction). Rather, I am using a mesh cell strainer to sit the embryos in and transfer through fixatives, washes and dehydration. Do you have a better suggestion for me? I was considering small wide glass jars with plastic lids (but I am not sure of the compatibility of the plastic with fixatives (Karnovsky's and Osmium tetroxide) along with cost. (Graduate student with limited funds and lots of SEM ahead!)