Question: Does DMSO have to be stored in glass bottles? Answer: There is a common misconception that DMSO has to be stored in glass containers. It arises from the fact that over a long period DMSO can leach chemicals out of some types of plastic. However, HDPE ( high density polyethylene ) is suitable for the long term storage of DMSO and it is packed and shipped in this by the manufacturers. If you buy DMSO in plastic containers they should be HDPE.   Question: Why has my pure liquid DMSO gone solid? Answer: DMSO has a melting point of 18 degrees C. This means that in the winter or on cold days in the summer it can become  solid. This is also a useful test of purity. If you dilute pure DMSO it will not go solid even below 0 degrees C.