Robin...To me it depends on where the smell is. Many times candles will help, baking soda and powders will help in drawers then laying wrapping tissue over it. I like to take musty items outside to the sun or clothesline too.
from what?? whole house,furniture,clothes,books,old cars/trucks,basements
I diffuse tea tree essential oil. I mix it with peppermint or lemon to make it smell better
I would use baking soda. You can set open baking soda boxes around the house to absorb the smell, you can also sprinkle it on your carpet, let it stand for 30 minutes and then vacuum it up. Another thing that works is lots of fresh air to air out whatever has that musty smell. Here is an article that might help as well - https://www.onegoodthingbyjillee.com/7-ways-to-get-rid-of-musty-smells/