Hair vinegars and hair tonics?

I've recently found out about hair tonics and hair vinegars and they really intrigue me but I don't really understand them?

For context, I have a very oily and itchy scalp and often use deep cleansing shampoo. I've heard that many people shampoo twice but when I do that with the deep cleansing shampoo it leaves my hair super "squeaky clean" and stripped feeling.

Do hair tonics and vinegars work as a second cleanse and has anyone tried them in tandem with deep cleansing shampoo? Also, has anyone noticed a huge difference when using them?