What is the best way to keep ants away from your hummingbird feeders?

I rub vegetable oil on the stand to keep the ants from climbing up it and around the holes of the feeder to keep bees from taking over. They are very aggressive to the birds and the oil does not bother the birds.

I use Vaseline on the stand.

Wal Mart has a little gadget that hangs below the feeder. It says it needs to be replaced yearly but I've had mine 2 years and it still works. They were located right beside the feeders and only cost close to $5.00. I used the Vaseline but had to keep reapplying it.

Vaseline or make a moat, doesn't have to be large, ants can't swim.

I made a water holder from hair spray can top! Hard to explain but it works!