Chris Brown -- How Dirty Did He Get?

Passing bystanders enjoyed watching Brown Moon Walk the trash in the bags!

Chris Brown will face an L.A. judge today -- a judge who wants to know if Brown got his hands dirty enough to satisfy his probation on that felony assault conviction in the Rihanna case.

Our sources say Judge Patricia Schnegg has been skeptical about the type of community service Brown has been performing in Virginia. She wants to make sure it's true hard labor.

Brown and his lawyer, Mark Geragos, will go before Judge Schnegg at 2 PM PT today ... and we're told they're armed with a list showing Chris got plenty dirty performing his community service -- one of Chris' specialties ... cleaning brush off Virginia highways.

We'll be live streaming in court.