Being made up of mostly water, watermelon stains look trickier to remove than they are. Whether they've found their way into your carpet or your clothing, it should only take a few basic cleaners to get them out.
Clean Watermelon Stains out of Clothing
Boil some distilled water. Pour it directly onto the stain. In many cases, this will remove it entirely.
Treat the stain by soaking it in an enzyme pre-wash soaking solution, if boiling water did not remove it. Leave it for at least half an hour, but the longer it soaks, the better.
Wash the article of clothing in hot water if possible. That should remove most treatable watermelon stains.
Get Watermelon Stains out of Carpets
Get a clean cloth or paper towel to blot up as much of the watermelon stains as you can. Work from the outside of the stain towards its center.
Add 1 tsp. of dishwasher detergent crystals to 1 cup of water. Soak a clean cloth in the solution and use it to blot the stain.
Work the detergent solution into the carpet using your fingers to make sure it reaches the roots of every fiber.
Rinse the detergent out of the carpet by following up the detergent solution with some plain warm water.
Repeat as necessary, ensuring that you remove every trace of detergent from the carpet when you've finished.
Treat stubborn watermelon stains, if they are still present after the carpet has dried, by mixing 2 tbsp. of ammonia into 1 cup of warm water.
Pour the ammonia solution into the carpet. Blot it dry with a cloth or paper towel as you did with the original dishwasher detergent solution.
Add 2 cups of water to 1 cup of vinegar.
Use the vinegar solution to rinse out the ammonia, in lieu of the simple lukewarm water you used to neutralize the detergent earlier. Blot up the vinegar solution using a clean cloth.