How to clean Kitchen curtains that have grease residue?

first I would soak them over night in Dawn dish detergent and very hot water. Then the next morning put them thru a wash cycle in washing machine. Dawn will break the grease up so they should come out grease free

Could try adding a little Simple Green or other degreaser in your laundry water.

Vinegar and baking soda and a little laundry detergent, let them soak for a while, possibly overnite, then see if they still feel greasy. If so, you may need to change the water and repeat the process.

If really greasy, do a vinegar soak overnight, cold water is fine. Then launder with your regular detergent, add in a few heaping tablespoons of baking soda to the wash and vinegar in the rinse cup - where fabric softener goes. Good luck!

You could also use some Awesome Degreaser from the Dollar Tree in a tub to soak, then run through washer.

Greased Lightening

I always soak my kitchen curtains in cold water with a degreaser like Dawn dishwashing detergent. If there are any heavily soiled areas I then add more dawn directly and use a soft scrub brush to cover that area.

Then just wash. I have always had luck with this method.

if they are cloth curtains- wash them in hot soapy water

Try soaking them in warm water and Dawn dish detergent. The blue one. But only if the fabric can handel warm water. Then wash them as you normally would, but don't rinse them before you wash them.