HW Products, Inc. (makers of the pad savers for the WW) now makes 'Brass Saver' products. I've used the trombone, baritone and trumpet set myself, and they recently came out with a set for tuba. They work very well with soft bristles and no exposed wires. Here's a link:
Miraphone 5050 - Warburton BJ/RF mpc YEP-641S(recently sold), DE mpc (102 rim; I-cup; I-9 shank) Symphonic Band of the Palm Beaches: "Always play with a good tone, never louder than lovely, never softer than supported." - author unknown.
LV wrote:I actually have the tuba BrassSaver, but I'd really like to find something a little bigger in diameter to do a better scrubbing. Thanks anyway!
Well, you could always take a bottle brush, cut off the handle and crimp the brush end to a length of bicycle brake cable casing...