I have a basic question too.... how/when do you clean them? Do I need to bring sponges with Dawn on them with me, or can I get them cleaned at the resort's quick service place?
It's a gross thought to me, just thinking about drinking out of the same cup for over a week without waching it. And the chapstick buildup - oh the humanity!
Not all the Quick Service locations have a sink for rinsing out the mugs and one location like that is Gasparilla's Grill & Games at the Grand Floridian.there is a sink for rinsing out the cups at the end of the soda fountain station. You can bring your own soap if you wish. Leave the soap in your room and just before you leave for the food court, squirt a drop of soap into mug...then rinse at the sink/food court. If the water at the sink is not hot enough, go to the hot water dispenser (for tea) and fill your mug there...take it to the sink & rinse.
To the OP I just wanted to say if you were staying at the Boardwalk Inn/Boardwalk Villas they don't have any self serve refill stations. At the locations where you get refills you show a Cast Member your mug and they give you a drink of your choice in a paper cup, because they are not allowed to refill the mugs. However all the Quick Service locations at the other WDW Resorts have self serve mug stations where you refill the mug yourself.
Use the HOT water dispenser on the coffee machine. AT least it will be sterile.

To achieve sterility, a holding time of at least 15 minutes at 121 °C (250 °F) or 3 minutes at 134 °C (273 °F) is required.

I, too, have a refillable mug question.
If we get the free refillable mug as park of the 2012 DDP, when/where do you get it? Do they have them at check-in or at a resort market time place? We're going in January and are staying at BC and this just made me think of it...
There will be a mug credit on your KTTW card. One for each person on your room reservation (over 3). Just grab a mug at the checkout counter and they'll "charge" your KTTW for the mug credit.
