They're clean in the photo because they were new. They have been used many, many times since the photo was taken. The worm is pretty much black like iron now.
As for the paint roller head, what do you think that is in this photo?
Actually, that's only half a roller head as it looks more in proportion to the other implements. This implement was built for show and not for use.
The heads I actually use are not as pretty (a lot shaggier), and are set up to be mounted on a shortened aluminum shotgun cleaning rod. Not historically accurate, but lots more efficient than a sponge on a stick.
The roller heads have a bronze shotgun cleaning brush pushed inside the center tube. Depending on the size roller that they were intended to fit, they will accept either a 10/12 gauge or 20/28 gauge brush. You can screw the roller heads on and off the rod just like any other cleaning tool.
The brushes are a very tight fit, and the bristles will hold the head securely even during vigorous scrubbing. But they can be pulled out to reuse when the head starts to get ragged.