I'm a bit OCD so basically wash them once a week after riding once or twice during the week.
CT18 mix in a spray bottle, spray on and let it soak for 5 min.
Rinse off with garden watering head, then sponge wash with bucket of car wash.
Let dry then re-lube. (love the blower idea, will be giving that a go)
I also use this method on my road bike with way less water resistance for bearings etc, no problems in 12,000km over 3 years.