Count me into the grout sponge game.
I've just converted to ONR wash, one bucket/grit guard method. First wash was with a new sheepskin mitt, second ONR wash tried the whole microfiber towel method, third wash using grout sponge.
My car is currently sealed with werkstatt prime + AJT, and I'm really impressed with ONR.
Sheepskin was surprisingly my least favorite method...maybe it's because it was a brand new sheepskin, but it just turned dirty as can be. I've demoted that sheepskin mitt (only used once) to wheel duty.
I liked using the microfiber for the wash/dry. You could really feel what your doing...very tactile. I think i'm just too lazy to have to wash microfiber towels that often.
The grout sponge easily held enough solution, and rinsed clean as others have stated. I bought two at home depot on a whim while going for supplies for another project...glad i did.
I only wish I bought a gallon of ONR instead of my trial bottle size.
So...count me in as an ONR convert. No hose required for last 3 weeks, and only 3 gallons of water per wash....what's that....2 toilet flushes?
By the way, are you guys using a regular plush microfiber for the drying process after washing a panel with ONR, or one of your waffle weaves?
--jason
Ps. I used an old pump dispensor from a shampoo bottle to dispense the ONR. For me its now 4 pumps = 1 capful. (12 pumps for 3 gals of water). quick and easy dispensor.