All the attention I pay to my spokes is to blast 'em with the hose after every third ride or something. I suspect they probably like having a little grease on there to keep things nice and rust-free. It's like the chain, you don't want to just blast away whatever protective agent it's got, particularly if you're doing so with a rust-causing medium like water, as in pressure-washing. A quick one-over on the rims with some moderate pressure is enough for me. If you want to do an "out-of-the-crate" restoration, I guess you'd want to detail it but I don't see any reason to mess with it otherwise.