I put vaseline on the hangers and the top of the feeder..It really helps on ants.Do carry a cloth to wioe your hands with after hanging up a feeder in 100 degree heat..!;)
That's usually what I do, and it works most of the time.
In the heat of the summer, though, the Vaseline 'cooks' and gets hard enough for the little buggers to walk across and get into the feeder.
Next thing I know, sugar coated ants!
:-)