Regular washing makes your towels lose their quality, softness and their natural color, no matter how expensive they are.
This trick will make your towels look like you just have bought them from the store.
First, do not put too many clothes and towels in the machine as they cannot be washed well. Put your towels in the washing machine and add half a cup of vinegar. Vinegar will soften the towels and clean up your machine, removing all the unwanted smells accumulated in it.
After you have washed your towels with vinegar, start the machine again, but this time wash them with water.