K5’s right? Wouldn’t panic about it. Just give them a blast - that’ll clear the water right out of them. They are cast alloy with stainless diaphragms so corrosion isn’t a huge concern unless it sits for ages. Water ingestion will not hurt them, just think of what they have to endure on a train.
I suppose what will wear them though is any kind of grit. If you get mud, muck, sand etc right into the back of them then that will no doubt wear the diaphrams and the seats. Diaphragms are easily replaced but the seats will need machining if you get them pitted.