After cleaning a bunch of greasy kitchens I have a bunch of rags I'd like to have cleaned and reuse. Best way?

First soak them in a wash tub filled with almost boiling hot water and lots of DAWN DISH SOAP ( 2 tablespoons). The blue stuff. It has to be that brand.

Stir them around to mimic the way a washer works. That will help the Dawn release the grease.

Dump the water and fill again with hot almost boiling water and stir again with no Dawn. Dump the water, wring out the towels and now you can run them through your washing machine with a good detergent and bleach and not worry about the grease fouling up and ruining your washing machine.

And you won't have to worry about kitchen grease smells getting on your clothes.

In your washer use hot water and detergent.

Ammonia is good for grease.