TOTEM Sttaf removing mass loading

Is the load compartment completely isolated from the rest of the cabinet on the sttaf?

yes, it's a separate chamber at the base of the speaker. It's purpose built for loading, and you're right - it's a trivial concern.

A few specs of residual kitty litter doesn’t weigh much, I would not worry about it. As long as there sealed up appropriately.

"totem also recommended ’beaks’...yeah, right."

The beaks can make a dramatic difference. I hung around while a friend tuned his sttaf’s long after they endured plenty of break in time. Then beaks were installed. Unlike a lot of flashy gimmicks they are one of those things that just work. After beaks were installed they were partially loaded with Sudbury nickel.

dfelkai I recommend trying both, beaks and mass. Run them bare until you get accustomed to them, then do a before and after. Don’t fill them up at one go. Gradually load, test, repeat. When you pass an obvious sweet spot remove a little. Weighing each time you add makes it easy.

Pretty sure that ship has sailed. The OP asked the question seven years go. But as long as we're on the subject almost all speakers have way too much filling inside. Most speakers sound much better with the bare minimum fiberfill, wool, what have you. Besides, Beaks aren't really mass loading, as it turns out. They are a point where resonance can escape the cabinets. 

Vac it off whatever remains. Plain and simple. You can also bring it to any automotive or tire shop so they'll stick blower in the port and blow it all out.

I haven't experience with cats much -- mostly birds, but my question would still be as follows:

Less-likely cat will go into the speaker port to do his/her litter business, but what if mouse gets there? Is it possible? They might leave some feces for sure there...