[vrokhlenko]

Yes. You can use castor oil or mineral oil. At least in the US mineral oil is much cheaper. The idea is to use as pure oil as possible so it would not affect o-rings and would maintain the same viscosity over the working range of temperature. Both castor and mineral oil satisfy these requirements. They are recommended for internal consumption as stomach remedies. I use mineral oil in my Mares Cyrano. My father has been using castor oil in his gun for at least thirty years.

Hope this helps.