Allways wash your reel with the drag done up tight to avoid forcing the salt further into the reel. Try not to spray the hose directly on to it in a jet. Muffle the hose with your hand or just set the nozle on a kind of a dribble. Alternatively use a bucket of warm soapy water and wash the reel by hand with a sponge or soft-bristled brush.
Once the reels have dried, a light spray with CRC, WD40, Tackle-guard or similar is a good idea before putting them away.
Every year or two drop your reels in for a professional service. It doesn't cost a lot to keep them in top condition and you'll be glad you did when you hook that fish-of-a-lifetime and your reel performs faultlessly!