1. Stored RNA is stable when it is precipitated in Elthanol or Isopropanol and kept at -80°C.
2. In DEPC treated water at -80°C in multiple aliquots to avoid multiple freeze thaw cycles.
3. Converting the RNA to cDNA and storing it in RNase free water in -80°C.
Souce: NovoPro 2018-02-07