Who cleans the Enterprise?

[RAMA]

Self-cleaning nanotech wouldn't be seen at all. It could be happening during whatever conversation we see. So no problem there. We've established it "cleans itself" we've established some level of nanotech on the Enterprise-D. Of course, that doesn't mean if some new dirt or contamination appeared in rapid succession it couldn't be cleaned up by the usual 24th-century macro-means like attuned phaser broom or the like.

RAMA

It could be the self-cleaning process is one or both of the following:

1. Done when rooms or sections are empty of human life (incase it's invassive to humanoids and escaped pets).

2. Slow and gradule -- it doesn't occur very quickly. Which would not only account for why we never see the self-cleaning ship actually clean itself and why Guinan whips down tables; she's not waiting for it to handle itself.