Umm..that is icky!
But don't feel bad, it's not nearly as icky as our boy's part.
I don't know what he does with that thing when we aren't around, but it is ALWAYS filthy. He gets hay on it, gravel on it, mud on it.....
....don't ask me how because I don't know....not sure I WANT to know. Then he gets this dried flaky stuff on "it", also.
Once I SWEAR there was sand on it....but that is impossible as there's no sand within hundreds of miles of us....but it did look like sand.
SOOOO....because he's a filthy pig, we have to clean it at least once a week. We dont' do the bean check though....we leave that to the vet when she comes for the spring vaccinations.