WD 30mm Boar - I've gotta ask...

... Can you load this brush with rocks instead of soap? It looks like it could plow through walls like the kool aid man.



It's really nothing more than a curiosity to me right now, but it'd be cool to know. Does anyone have this thing? How does is it after break in? Does it soften, or does it forever function as a soapdozer? If it is truly the backbone mafia, how's that working out for you?



Haven't seen too many like that... Is there anything similar out there that I've overlooked?

WD 30mm Boar - I've gotta ask...