Assuming that you can I would put them in the clothes washer on the cold water setting and some vinegar. I would avoid putting them in the dryer and hang them back up and let them air dry.
Hi Christine: You could lay them out on the floor and (I'm assuming here that they are the lined curtains) use a sponge and some warm water and a bit of Dawn dish washing detergent. Then, change the water and use clean water and sponge to rinse. Hang back up and you should be good to go. :) Good luck
I've had some that the backing pucker on if in a top loading machine. With a front loading, use a delicate cycle, cold water and don't put in the dryer. If there is care label, check it before cleaning.
Since the backing is inseparable from the fronts, then consider that UV has discolored them. Has it?
Hi Christine. You could use the upholstery brush on your vacuum and run it down the length of the under side of your curtains. If the curtains have a build up of dust, this method should work well for you.
I would wash them by hand. Is there a lining? If your curtains don't have a liner, you can wash them by putting them in the delicate cycle in your washing machine, on cold/warm so the color is maintained. However, if you have a backing liner, you will want to wash that by hand and air dry it. The liner is a completely different material and will shrink up compared to the curtain front if put in your machines.... and because of that, they will not hang right again. Also if these curtains have pinch pleats, be careful when washing. You don't want to mess up the tailored folds. Good luck!
Hi Christine, you can just take them down, give them a good shake to get rid of dust and put them in your washing machine on a gentle cycle, in cool or lukewarm water, and use a mild detergent.
Here's a post that might help - https://housewifehowtos.com/clean/how-to-clean-curtains/