I like to use a dictionary to list all attributes I need to save and store the whole dictionary on local storage as a JSON. Here's an example of how you can do it:
https://www.dropbox.com/s/9owz32wd935lq ... .capx?dl=1
In this capx I have 3 swords which can be owned or not (just click on the checkboxes to change state) and a death count that you can increase by clicking the Kill Player button.
Hope this helps. Cheers!