Sodium ethylate

(Sodium Ethoxide)
C₂H₅ONa   F.W. 68.05   CAS #141-52-6
Used as an agent for flattening thick sections (0.5-2.0 micron) of epoxy embedded material. Felix Sierra, Christa Hegele-Hartung and Henning M. Beier (1990).
An improved technique for flattening semithin sections of epoxy-embedded tissues used for high resolution light microscopy. J. of Microscopy Vol 159, Pt 1, (July 1990), pp. 95-98