Try 1 tablespoon of ammonia mixed with 1 cup of water but not on wool or wool blend carpet.
Tiny black spots on carpet.
Next blot the area dry with a clean dry cloth or paper towel.
To rid your carpet of foul smells first blot any strongly affected spots with a damp cloth.
Instead use mild detergent and water.
Only wool carpets and nylon carpets will accept most dyes starting in a hidden or at least not obvious area of the carpet mix 1 cup of distilled white vinegar into a1 gallon of warm water and spray the carpet test area evenly enough to wet the top of the carpet fibres.
If that doesn t work you can try one part chlorine bleach to five parts water but only on solution dyed carpets such as polypropylene.
If you get to one of them and sort of pull the carpet fibers back it looks like it starts at the very bottom of the carpet where it s woven into the backing and it s very very dark almost like.
Sadly the case of black mold on the carpet will not be visible straight so it s better to send it to the nearby laundry to get it cleaned and has proper drying.