Indigo Vat Troubleshooting: Greenish Tint

Q: My vat has a greenish tint to it, is something wrong?

A: The vat should always have a greenish tint, though the oxidized indigo on your fabric should always appear blue. If there is a greenish tint there, you hit the sediment when you were dipping and your piece has got iron crud on it. You can wash with citric acid and soap alternatively until the piece goes back to pure blue. Avoid the sediment, but if you do get some on your piece, rinse it off immediately and THOROUGHLY.