How do I remove plain black decaf coffee from light blue carpeting?

Here are some things to try

https://www.goodhousekeeping.com/home/cleaning/tips/a16166/stains-coffee-may07/

https://www.thespruce.com/removing-coffee-stains-from-carpet-1901013

https://m.wikihow.com/Remove-a-Coffee-Stain-from-Carpet

1. Apply a mild soap or detergent to the area and gently work it by rubbing the fibers between your fingers. Avoid pushing down as you rub as this will push the stain further into the carpet.
2. Spray with water and blot several times to rinse.
3. If there is still some staining, apply a foamy shaving cream to the area and rub it gently with a clean cloth.
4. Blot to remove. Repeat as necessary.
5. Rinse by spraying with clean water and blotting with a clean cloth.
6. Still got staining? Make a paste with baking soda and water. It should be the consistency of toothpaste.
7. Spread the paste onto the stain and allow it to sit and dry.
8. When it is dry, vacuum it away and the stain should be gone.

Maybe this will help you Sandra. https://www.hunker.com/13423424/how-to-remove-old-coffee-stains-from-carpet