Under the heading of "don't try this at home", but I tried it and it worked -
I dumped a jugful of Adnams' Broadside over the keyboard of a Mac a couple of years back. Broadside is devilish sticky stuff, but I just unplugged the board and chucked it into a sink full of clean cold water. A good shake and a drying off in the airing cupboard and the keyboard worked just fine afterwards.
I can't guarantee that everyone will have such a happy ended from dunking a keyboard, however. If you try it and fry it, don't sue me!