I use an ozone machine like this-
https://smile.amazon.com/Ozone-Power-OP5000-Commercial-Generator/dp/B012OW48M2/ref=sr_1_7?s=home-garden&ie=UTF8&qid=1516656077&sr=1-7&keywords=ozone+machine
It completely removes smoke odors effortlessly. I presume it would eliminate musty odors.