When washing a plastic shower curtain, retard the formation of mildew by adding half a cup of table salt to the rinse water and allowing the curtain to soak for fifteen minutes. Drain washer and remove the curtain. There's no need to spin.
To prevent mildew be sure to spread the shower curtain open after taking a shower. If the shower curtain mildews at the bottom it's probably because it is allowed to rest against the bottom or side of the tub. Try to reposition the bar so that the curtain can hang loose and dry between uses.
By Ron from Cortez, CO
If you buy one of the new cloth curtains, they can be thrown in the washer and hung back up. I wash mine at least every two weeks and leave the rings on it. They cost a little more but you will never have to mess with a plastic curtain again and these cloth ones last for years. I have two. One on the outside of the tub and one on the inside. They do not leak through.
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I always make sure to cut the bottom edge off, where it has a hem. The hem collects moisture and it's almost impossible to keep it clean, even with bleach.
When you purchase a new shower curtain liner or plastic curtain, spray the bottom with vinegar and it will not get mold on it. I got this from a friend many years ago
Many older homes can have problems with mold and mildew in the bathroom. Preventing it can be difficult because dealing with the excess moisture must be dealt with before any mold can be eradicated.