Go easy with the fan if it is heated air.
I've no idea of the construction of your keyboard, but a week in an airing cupboard might not be long enough depeding on how close plastic laminations are to one another.
I have a horrid feeling that you may already have done some irreversible electrolytic damage.
Remove the battery and disconnect from the mains.
Discover how to remove the keyboard and dismantle as much as you can.
If there's anything that can be wiped clean with a soft damp cloth so much the better. Then when you are satisfied it is as clean as you can get it leave somewhere like an airing cupboard for as long as you can and a bit more for luck before reassembly and an offerring to the patron saint of computers whoever that my be!