A Firefox add-on that will automatically redirect to the Amazon Smile site only when it verifies a signed-in status. Only purchases made on the smile.amazon.com site count toward amazon donating to the charity you choose. Permissions used include cookies and webrequests. No information is collected. Please report any bugs you find, and if anyone can design a better icon please feel free to submit one. If you aren't already signed up for Amazon Smile I would like to suggest the Ingham County Animal Shelter https://icasfund.org/donate/
Also works in private browsing - Instructions.
More information on Amazon Smile.