Finally broke down and bought the Mr Clean car wash "device". It works as advertised, but after just one car wash, the ionic filter was black. They claim up to 10 washes per cartridge. Toward the end of the wash, the last section of the car didn't dry, so I guess the cartridge doesn't last that long. When I add up the cost of the soap and ionic cartridge, it's about 5 times more expensive to use than the old method (car wash concentrate and leaf blower drying).