Even the most expensive of towels can become stiff and lose their absorbency over time. The main culprit is fabric softeners. These coat the fibers of the towel with each wash until they repel moisture and each little fiber is stiff and scratchy. Once they begin to repel moisture, it can be more difficult to get them clean. This can cause them to smell musty as well as being stiff. You can soften towels without harsh cleansers and special products, but instead with common household items.
Measure 1 cup of Epsom salt and add it to the towels once the washing machine has finished filling with water. This will remove excess dye from new towels and chemical build-up from older towels that is stiffening the fibers.
Add 1 cup of white vinegar to the towels during the rinse cycle on your machine. This will soften the fibers in the towels.
Place half the amount of towels your dryer can hold into the dryer and dry as usual. Small loads ensure that the fibers do not become compressed and that the towels can fluff properly.
Continue to add 1 cup of vinegar to the rinse cycle each time you wash your towels. You can repeat the addition of Epsom salt if the towels stiffen again.