Did some searching but couldn't find my answer.

Sounds weird but I've made this a bunch of times and have always used all of it.  This time I have some leftover and am wondering how to store it.  I thought I read to keep it in a cool dry space.  Also, how long will a batch last?

Thanks

I freeze it when I have it left over.  Just bring it back to room temperature and put it back in the mixer before you use it.  I've also left icing in the fridge for at least a week when I know I'm going to use it again fairly soon.