how long can i store used cooking oil before processing it ot biodiesal Submitted by an Anonymous Greaser on Sun, 2008-11-23 01:35 i have used cooking oil how long can i store it for use in making biodiesal Reply to this post I have the same question. Is Submitted by an Anonymous Greaser on Wed, 2009-01-21 23:56 I have the same question. Is there a shelf life when storing used cooking oil prior to processing the biodiesal. reply I have stored wvo that I have Submitted by an Anonymous Greaser on Mon, 2009-02-02 15:32 I have stored wvo that I have filtered for over a year. I put a purge of argon on the oil so there is no contact with air. Argon is heavier than air so a few minute purge and good to go. reply Reply to this post Your name Comment * Location * What code is in the image? * Enter the characters shown in the image.