Yes, you open it up and take the floss out and rinse it out. It takes a little bit to rinse out, but it will. But it's cheap enough where you can just replace when it's time. The bio-wheel takes care of the bio-filtration, so there's no worries there.
Also, since the inner one will be cleaner, you can just replace the floss in the outer one, move the inner one to the outer position, and put the one with new floss in the inner position.
55G Filstar XP3 - 16" Fire Eel
75G Medium Planted - Filstar XP3 Low Light - Established Feb 2006