My brilliant/interesting/talented Aunt Clare passed on this lovely lil tip to help us all create the most fabulous hand crafted dish cloths:
Lily Sugar n Cream cotton yarn works well and is widely available and relatively inexpensive. It's a soft yarn, but the knit and purl knubbies act as gentle scrubbers.
The crocheted versions would likely be flatter (no knubs) but would also be denser and perhaps last longer. My knives cut mine up after a year or two of use, but I enjoy making them and can easily knit one during a nights-worth of TV. It's great having a project I can start and finish in one night.There we go, advice from the expert herself.