The fully assembled keyboard? or parts of said keyboard.
If fully assembled, you psychopath. I would recommend washing your mobile phone in the dishwasher also (those things get pretty dirty).
If parts I would wash by hand with warm soapy water for example the outter shell of the model M AFTER it has been dismantled. The last lot of keys I washed from a Model M I just put in a tub of warm soapy water and didn't bother actually scrubbing and they came out quite nicely.