Thank you very much for your question. It is our pleasure to answer it.

In the name of Allah, We praise Him, seek His help and ask for His forgiveness. Whoever Allah guides none can misguide, and whoever He allows to fall astray, none can guide them aright.

Dear sister, vaginal discharge (which scholars call "Rutubat al-Farj") is a white discharge that many women have with or without a cause.Whether this discharge is pure or impure and whether it nullifies Wudu` or not, there are the following details:
1-If it comes out of the external part of the vagina, then it is pure (tahir) and doesn`t nullify wudu`.
2-If it comes out of the internal part of the vagina, then it is also pure, but nullifies Wudu`. Therefore, it is imperative that she makes Wudu` whenever she has this discharge. However, you don't have to wash it off your clothes unless you are certain that it came from the depth of your womb similar to the discharge that comes upon delivery. In this case, it is impure (Najis) and requires washing the clothes off.
3-If your aren't certain where the discharge came from, then it is pure and doesn`t nullify wudu`, because certainty can`t be removed by doubt.

And Allah Knows best.