I personally DO NOT WASH my Microfiber.
I run mine through steps, and I have a place for each step in the garage. I only use them for each step a coupe of times. It is my own recycle system.
Step 1: Painted Area and/or Chrome - Either drying, Detailing, wax or polish. (Once I use with a cleaner or other product, It only moves past here if it works for the next application)
Step 2: Next use is for Door Jams, Under Hood, Interior Surface, Rims
Step 3: Next use is for Engine Plastic Wipe Down, Inside Wheel Wells, Under Body, Tire Cleaning
Step 4: Wipe out Exhaust tips when I come in from a ride, pick up grease, Tire Protectant
Step 5: Garbage
Depending on how hard your water is, I think washing them only gets out but so many contaminants and can lead to micro fine scratches in the painted areas...........so I say, Limited USE ON PAINT ONLY. The only exception I have to this is the waffle textured micro fibre drying cloth to dry the car. For that I have one for painted area's, one for the rims, and one for area's that are harder to scratch (Rear Valance, Under Hood and plastic pieces, etc.)
Keep in mind my car is garaged and not driven in bad weather. This could be expensive for those who store the car outside and wash it all the time.
SIDE NOTE: I LOVE THEM PLUSH MICRO FIBRE CLOTHS FROM ADAM'S, now those are cloths!