Hi, you can put your shower curtain in the washing machine - 40deg is probably best but it definitely won't melt! Just don't put it in the tumble drier!
Remember that it won't spin-dry properly since the water can't pass through the plastic. So be careful removing it, or you could have a very wet floor!
Have a look at your shower curtain fender? Why that's very nice of you, give us our address and we'll be there. We can make a bit of a party out of it, it can be called a errrrr shower shower.