Back in the day cotton bath towels or nappies (diaper-US) were the things available to clean the car (IMO cotton terry does cause miro scratches) or an old T-shirts. With the onset of cheaper synthetic materials (polyester) they became very hard to find.
Now my replacement for the above (although I still use T-shirts for engine or wheel cleaning) is 100% cotton micro fibre towels (DF Towels or the Autopia Buffing Towel)
JonM