"Terrible problem " means what to you? Lots of stings? Swarming of the HB feeders? Can't sit outside?

I can point out a few things which might save you some time. Vegetable oil will do nothing to deter the insects, for one thing. Eradication of the YJs is not possible, nor is it desirable. Would moving the feeders solve the problem? What about removing them and planting more nectar-rich plants?

I am sympathetic with those dealing with large numbers of YJs. In warmer climates, they can build nests of enormous proportions, containing multiple queens and year round activity. That's unusual, however, and occurs only in undisturbed, protected locations.

Please give us more information and perhaps we can help.

Yellow Jackets can be a real problem at Hummingbird or Oriole feeders especially in the spring when they are more interested in sugars than proteins. Yellow Jackets are not really pests but are beneficial because they do prey on many of our insect pests. There are bee guards available for these feeders that can help and they are about the only thing that will.

this is why.. i stopped using the feeders.. especially when the kids were young..

two neighbors have feeders.. and complain all summer long.. but the hummers come and nest in my conifers ...

get rid of your feeder.. and plant some plants that attract the birds.. and your problem will go away ...

in trying to outdo mother nature.. you are creating an attractive nuisance.. and then complaining the YJ's are attracted.. soooo.. try something else ...

or just go hang the feeder across the yard .. further away from you.. and get some binoculars ...

my local hummers.. [and BTW.. you might want to do another post specifically titled for plants that attract such... ] mine are attracted to ... hosta ... especially the late bloomers that are fragrant.. honeysuckle vine .... my old redbud.. but i think they just liked the tree.. as it bloomed long before they were in town .....

it seems.. or i just see think .. in later summer.. they are attracted to fragrant stuff ... 4 o'clocks ... i am thinking.. but am not sure of autumn clematis .....

ken