in context : if one is just rinsing off the surface dirt with a karcher and then washing with a Mitt I would say 2 bucket method is essential. Note car kept outside, 3,000 miles per annum so fairly clean. But re my temporary regime to avoid lifting etc. Post back op. :- 1. Power wash with an Industrial Karcher 690L per hour for 30 minutes 2. snow foam thick blanket ... wait 5 mins 3. Long power wash completely off say 30 mins 4. Then lightly wash with AG body shampoo applied by snow foam gun using microfibre noodle mitt .. i.e. just the weight of the noodles 5. Quick power wash off say 10 mins 6. Then wash with a bucket and autoglyms shampoo using Wool Mitt properly. Obviously squooshing out the wool mitt each swipe, and not going near the bottom of the bucket. On the last 2 activities there appears to be no difference in quality of soapy water in either bucket ... So would you agree there is no point in using 2 buckets and rinsing the mitt in fresh water between each swipe? My thoughts Until the back is totally healed circa 4-6 weeks more ... hey its good enough my back is far more valuable than the odd swirl. But once fully healed I cant see the point. But open to advice.