@lucy yep! they come apart. The front just unscrews and the filter is just on that part that came off.
As for maintaining/cleaning, maybe dunking the filter in isopropyl alcohol and swirling it around a bit, then letting dry and replace could fix it, but risky.
I think you can find replacements for the filters on one of the various e-commerce sites...

search term on funny rainforest site "moondrop filter"