Clorox disinfecting wipes are a marvelous invention.

We use them to wipe down countertops, headphones, keyboards and mice, and even books. The lemon-scented ones help knock out the leftover cigarette smell some books have.
We're still using the Labtec LT-835 headphones like those we first got with our Gates machines (we liked the design, especially the inline volume control). We've purchased replacements via eBay, but the original model is rarely found, there's a newer version. We just got our first pair, and they seem a bit stronger in their construction.
We clean them as needed with the wipes -- not only the earpiece but the entire headset -- and we usually do the keyboards and mice at the same time. We tend to do this more often during cold and flu season.