Vinegar cannot remove hair dye.

More Info: Vinegar can often cause fading effects on dyed hair, but it cannot fully remove semi-permanent or permanent hair dye. While vinegar can sometimes clarify one's natural hair color, it cannot remove dye from the hair completely.

A common and well-circulated beauty misconception touts vinegar as a hair cure-all. With semi-permanent dye, especially fashion colors outside the natural spectrum like red, pink, and purple, vinegar only fades or changes the tone of the color. Semi-permanent and permanent hair dye must be properly removed with chemical compounds uniquely tailored to the makeup of the dye. For best results, consulting someone in a salon will lead to the restoration of natural hair color and complete removal of the hair dye. 

Since vinegar fades dye, it can be used to remove dye stains from surfaces like floors and sinks.