They recommend to use their cleaner, but I guess you can "hose it down" as you said. If you read their instructions, they actually claim that the dust works for it, as it creates a better filter, of course too much dirt on it will make it difficult for air to get in... I got the box that has the cleaner and filter oil, and it works great. I also had to wah the filter with soap once as it got too much grease on it, but then I did the regular cleaner and then the oil and it just looked like new.
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