View Single Post
If you select them and then click on the delete button, they'll be deleted. Of course, it's a good idea to know what you're deleting!

If you select something that OmniDiskSweeper can identify as part of a system package, it will show you that information, as seen here:

Unfortunately, the absence of such an indication is not a guarantee that it is safe to delete the file. Also, OmniDiskSweeper destroys the file immediately without involving the normal "empty the trash" mechanism, so don't delete something thinking you can undelete it. If you really want to delete it like the Finder does, you can double-click on a file and OmniDiskSweeper will open a Finder window to the file, where you can do what you want (move to trash, get info, try to open it, etc.) My philosophy is to avoid putting valuable files in the trash however briefly :-)

What are the multi-gigabyte files that it is turning up for you?