Amy a.black light to see mess is better than black light, the uv light to be powerful enough to kill bacteria can melt your eye corneas.
For disinfecting masks you can get good cloth boil with bleach clean. There are new masks like https://www.vogmask.com/ that last for months and are washable with .3 micron size mesh. It’s good for bacteria but will fail on most viral filtering.
Link to what size standard particles are https://www.engineeringtoolbox.com/particle-sizes-d_934.html
.3 is hepa filter which is standard hospital filtration, beyond that is mainly for biolabs, military installations.