Definitions of wash out:

• verb:   lose color in the process of being washed
• verb:   drain off the color in the course of laundering
• verb:   deplete of strength or vitality
• verb:   wash free from unwanted substances, such as dirt

  Example: "Wash out your dirty shirt in the sink"

• verb:   wear or destroy by the force of water
• verb:   prevent or interrupt due to rain
• verb:   remove by the application of water or other liquid and soap or some other cleaning agent

  Example: "He managed to wash out the stains"