What a difference using 2 buckets make versus only using 1 !!! If you are still only using 1 bucket for a wash you need to see what dirt and grim is staying in your wash water, and potentially staying on your mitt and going right back onto your car...
The blue bucket is my soap bucket, and the yellow bucket is my mitt-rinse bucket. I knew that the yellow bucket would have a lot of dirt, but I was amazed that the blue bucket had absolutely no dirt showing up. This should convince you to use the 2 bucket method and rinse out your mitt frequently and definitely before putting it back into your soap bucket.

The blue bucket is my soap bucket, and the yellow bucket is my mitt-rinse bucket. I knew that the yellow bucket would have a lot of dirt, but I was amazed that the blue bucket had absolutely no dirt showing up. This should convince you to use the 2 bucket method and rinse out your mitt frequently and definitely before putting it back into your soap bucket.