If you’ve never thought to wash these, you’re not alone.
Putting these through a spin cycle is really important, especially after a sweat sesh.
The outlet notes that summertime is high time to wash your scrunchies since you’re likely sweating more.

If you’ve been exercising outdoors, this is particularly important.
The main culprits here are your scrunchies.
While it’s not life-threatening, it’s definitely gross.

Towash your hair ties, Mindbodygreen suggests gently hand washing them.
Roll them out on a clean towel and hang them up to dry.
They’ll stay put and get clean right along with the rest of your clothes."
Well+Good suggests purchasing hair ties that have copper fibers inside these naturally repeal various forms of bacteria and fungi.
Otherwise, plastic ties will stay cleaner with fewer washes than any that are made of various fabrics.