How do I try out demos, but revert back to default?

I am building a site using the default template, but I like features I have seen in some of the demos so I want to load them to see the settings. For example, I want to see the settings for the icons in Beauty 2. How do I load the demo, but be able to revert back to what I was working on in the default template? I tried doing that and lost my custom CSS changes I had made to the default. Thanks!