Use the Stiffler to to scrub your chainring, chain, mech and cassette and use it to 'paint' degreaser and chain cleaner onto your mucky bits.
Short, stiff bristles work great on grime and the long handle makes it easy to dive deep into tricky areas.
As with all things, go steady. Excessive rubbing or pressure won’t do any good and could lead to surface scratching. For really sensitive bits, we’d recommend a sponge or microfibre cloth.