Here are some simple ways to get rid of ketchup stains.

  1. Flush with cold water from the back of the stain.
  2. Pretreat the stain with a liquid laundry detergent, tamp it down, and set it aside for a few minutes.
  3. Rinse well.
  4. Sponge with white vinegar.
  5. Rinse well.
  6. Steps 2–5 should be repeated until you have removed as much of the stain as possible.
  7. Pretreat the stain with a prewash stain remover before laundering.
  8. If the stain persists, rub it with liquid laundry detergent before soaking it in warm water for up to 30 minutes.