I have had very good luck with Tanglefoot. Specifically Tree Tanglefoot
Pest Barrier. I don't know what is in it but my organic farming son-in-law
uses it so it can't be very toxic.
It works beautifully but I apply it with a Q tip & try to leave an area
clear so I can refill without getting into it myself. I still have to clean
my hands occasionally.
I also have one feeder that has a built in water well around the central
stem. This also keeps ants out.
Bob Norton
Joyce (near Port Angeles), WA
norton36 at olypen.com