How do you separate modified and non-modified saves?

Hi all

The latest Interworlds update made me want to dive into mods (again - last time modified was X3). However, I also want to keep my non-modified saves. I mean, I could decide to take fixed slots for modified and non-modified. Also, I could manually backup/restore the saves locally on the disk. The latter might confuse Steam's cloud saves, though.

How do you handle this?