OO makes a very strong color fast yellow dye. I used to do natural dyeing demonstrations. I used sawdust or small chips. The wood needs to be boiled to extract the color. For good yellow it must be prepared in a non-reactive pot. Stainless steel or a porcelain pot with no chips. Iron in contact will act like a mordant and cause OO to be olive.(OO dye was used for Army green until after WWII) . Natural dyeing is a festinating study and even wood working related. Many other woods have been used for dye properties for centuries.