Remove your shower curtain and liner. Be careful not to drag them on the floor. You may not need to clean the shower curtain itself. The shower liner is both easier to clean and the part that is likely to be dirty. If your shower liner is very soiled, then you may need to replace it.
Place them in the washing machine. Separate the curtain and liner, then spread them out. Drape each around the agitator in your washer, or loosely place them in the tub if you don’t have an agitator.
Add two to three old towels. Towels will help remove some of the stains from your curtain and liner because they will scrub against them in the wash. Use medium to large bath towels. Add your regular detergent. Unless the label specifies otherwise, you can wash your shower curtain and liner with your normal laundry detergent. Avoid using fabric softener.
Check the label for the recommended wash setting. If none is recommended, wash on a normal setting. If you are washing your (non-color) liner without your shower curtain, then treat it like you would your whites, washing it on hot with optional bleach.
Hang dry or tumble dry low. Shower curtains and liners can easily shrink, so follow the care directions on your items. If you choose to tumble dry your liner and curtain, do it in 15 minute increments because they will dry quickly.