Dish cloths are the amazing little towels that everyone needs but few people actually ever think about. What makes them fabulous for crocheters is they are the perfect medium for trying new stitches and patterns. The dish cloth is essentially a swatch of material - for crochet and knit, think about a 10"x10" square.
What makes them practical is that they don't need to be out of a fancy, high-end yarn. A worsted weight or 100% cotton yarn will work the best. Lily Original Sugar 'n Cream is what I used for the cloths show above, though I've heard a worsted weight such as Red Heart works great as well for scrubbing.
Every one needs dish cloths. They may not be practical to mass produce to sell at a show, but they can be personalized to fit a friend's kitchen decor and given as part of gift basket or house warming gift.
Happy Crafting All!