Agreed; this is good advice. Wheels aren't cheap, so your apprehension is understandable, but a wheelset like your Rolfs, like most sub-$1000 rollers, is pretty much just an aluminum hoop. You can scrub it with all sorts of things and not cause a problem.
When you're scrubbing, your chief concerns are aesthetic. You might not want to dig into any decals or adonization. Really, the only super no-no is to keep oil AWAY from the rim. The rim won't mind, but your brake pads will never forgive you.
Dorian's right in that you don't want degreaser or water to get inside your hubs, so caution is in order, but it takes a pretty collosal flub to really make a mistake. The typical caveats are 1) no pressurized water, like from a hose, near the hubs, and 2) when cleaning the hubs and surrounding area, use a degreaser-laden rag, rather than dousing or immersing the unit.
No problem.
Good luck!