polyester vs. cotton for homemade dish cloths?

[frugal.lass]

I'm in need of some dish cloths (to clean dishes with, not dry them) and was thinking I would knit some up with some leftover yarn I have lying around. Is there really any difference between using polyester and cotton yarn for dish cloths? I have cotton yarn but they are unused skeins and I would rather save them for a larger project but I'm not sure if there are any reasons why I "should" use cotton over my poly yarn. The assorted rags I previously used to scrub my dishes with (until they were moved into the shoe polish kit) are of random materials...mostly cotton Ts but I know there are some polyester rags in there too. I know I would want cotton cloths to DRY the dishes with but when I'm using the cloth to scrub dishes in the sink...does it matter?

I'm probably going to whip up a few quick poly ones and see if they "do the job" but was wondering why cotton is the "preferred" wash cloth choice.

[Patty A]

I do some cotton dish rags in crochet patterns. I like the cotton best as it dries faster, doesn't shrink or lose its shape.

[homesteadmamma]

I use cotton too.