I wash mine at a self serve place called "Pitstop" on High street Reservoir - near the KFC and Caltex.
$2 for 2 mins. Reasonably clean bays, the soap seems nice and strong especially on Tuesday nights - I'm guessing this is when they re-stock.
They have hand wash service during business hours and weekends - but I've never used them for that.
Tends to get 'crazy' busy, especially when the weather starts warming up.
Anytime after 10PM it is deserted.
I usually wash my car there after a night out - around 2AM.