The best mold killer that you can buy commercially available is RMR-86 Instant Mold and Mildew Stain Remover Spray.
Other good mold killers are.
Tilex Mold & Mildew Remover 16 Fl Oz.
Concrobium Mold Control Household Cleaners.
Professional Disinfecting Mildew, Virus & Mold Killer – Cleans & Deodorizes, Lemon Scent.
Mold Armor Cleaner.
You can also use bleach to kill mold as well.
Bleach is another very effective mold killer.
A bleach solution also works to kill mold.
Mix one cup of bleach in a gallon of water, apply to the surface and don't rinse.
Mix a 50/50 solution of ammonia and water. Spray on the surface, wait two to three hours, then rinse.
Ammonia is also good to kill mold as well but just don't mix the ammonia and bleach together as it creates a very toxic gas that can easily kill you.
Black Mold can be dangerous and can cause breathing issues as well.
If you have black mold the black mold should be removed from your home and black mold could also be hidden behind drywall as well.
In those cases you need to remove the moldy drywall to get rid of it.
Black mold can kill you if you already have breathing problems or you're very young or very old.
It's still not a good thing to breathe in black mold spores or live in a house where mold including black mold is hanging around and growing.
If you do have black mold in your house it needs to be taken care of because not only does the black mold look bad it can also cause health issues in some people.
Any type of mold should be gotten rid off using bleach or something else to kill the mold.
If the mold is in drywall you should cut out the moldy drywall and clean behind the wall and then replace the moldy drywall with fresh new drywall.
Bathrooms are more prone to getting mold including black mold due to the high moisture content in the bathroom.
Using a vent van to help draw out moisture can help keep the mold from happening.