X mom

Some rooms accumulate a lot of junk. Valhalla-like painting rooms tend to be left with lots of paint, and other almost random rooms are sometimes filled with huge piles of props.
These messes are sometimes inconsiderate or accidental, sometimes deliberate intended to crash or lag innocent passerby (at least, my Windows client disconnects occasionally when faced with a room piled-high with dozens and dozens of props...).
Fortunately, rooms can be made self-cleaning. Just toss this little scrap into a script spot:

ON LEAVE {
    { CLEARLOOSEPROPS PAINTCLEAR } NBRROOMUSERS 2 < IF
} 

And the room will clean up whenever it's left empty.