We regularly used to put keyboards through the dish washer - when they failed that was the first thing we did. They HAD to come out before 'dry heat' cycle or the plastic would distort. They then were left open to dry for a week. A good 95% of faults were cleared this way, and there's no better way of cleaning keytops !
Essential though to pull them before the dry cycle, then let them dry naturally over several days.