Dryer sheets....wow these things are bad. For the last year or so, I have not used any kind of fabric softener in the wash or dryer sheet in the dryer. Why? Because these things are honestly bad for us, and we dont even know it. If you read a box of Bounce dryer sheets, it explicitly states right there on the box to not allow the product to come into direct contact with clothing......huh? Yes, you read this correctly, it says it right on the box. The same goes for liquid fabric softener. I think it was Snuggle that I looked at and it actually states on the bottle to not use with cotton.....???
Anyway, I have stopped using all products like that, and am now using these spiked balls that go into the dryer, and find that they work just as well as the dryer sheets and fabric softeners by "fluffing" the clothes, and I'm not exposed to all these harmful chemicals.
Here's a test you can do to see what's going on in your dryer when you use dryer sheets. Take a mirror, any mirror, and spray it with water. Then take a dryer sheet and wipe the wet mirror like you would a paper towel to dry it off. Watch and see what happens to the mirror. The dryer sheet releases its chemicals and your entire dryer and all of its contents get coated with these chemicals, not good.
There are a lot of reasons why mf towels shouldn't be dried with dryer sheets, I'm sure, but the one that sticks out in my mind is the fact that every time you expose them to these softening chemicals you are reducing the amount of liquid they can absorb. That's right, you are effectively ruining your towels. They will eventually start to just smear water around, and what's the point of that?
I suggest drying your towels on the lowest heat setting, and finding some of these dryer balls, and throw some of those in there. I don't even dry mine completely. I let them get about 80-90% dry and then take them out to air dry the rest.