Keeping a wallow "clean".

Hi y'all,

Another newbie question- I've seen it said (on the internet) that one must keep a wallow clean for the maximum benefit. I've seen the pigs pee in the wallow, and I understand that there might be some feces included. I can testify that the wallow is the stinkiest place in the enclosure. So, the question is, should I be "cleaning" the wallow, and if so, how the heck does someone go about that?

Thanks in advance!