Sometimes diesel oil or kerosene are mixed in before shipping to retain liquidity; upon delivery, these lighter materials are separated out of the mixture.
sˈʌmtaɪmz dˈiːzəl ˈɔɪl ɔːɹ kˈɛɹəsˌiːn ɑːɹ mˈɪkst ɪn bᵻfˌoːɹ ʃˈɪpɪŋ tə ɹᵻtˈeɪn lɪkwˈɪdᵻɾi; əpˌɑːn dᵻlˈɪvɚɹi, ðiːz lˈaɪɾɚ mətˈɪɹiəlz ɑːɹ sˈɛpɚɹˌeɪɾᵻd ˌaʊɾəv ðə mˈɪkstʃɚ.