I think you could only claim incidentals - it was hard to find a definition of these - and all I could find was:
OUS establishes the definition of incidental expenses. Incidental expenses are combined with meals into a single rate and include, but are not limited to, expenses for laundry, cleaning and pressing of clothing, and fees and gratuities for services, such as for waiters and baggage handlers.
This was from a random google search that I am using as a bench mark. So if your employer pays laundry fees then you might be out of luck.
I need to think about this as my potential deduction is over $4000 - and I havent spent that on laundry fees