Glad you asked...
You can preserve onions in vinegar. Without using artificial preservatives, vinegar is the best way to keep onions. Slice the onions, put them in a Mason jar and fill the jar with vinegar. Put on the seal and the ring and tighten it up. They will keep in your pantry for a long time.
CaroleM     How-To Expert
Other How-To Questions
About   .  Privacy   .  AskEraser   .  Settings   .     .  Careers   .  Ask Answers   .  iPhone   .  Help   © 2013 Ask.com