OK, this sounds strange but I used moth ball flakes. If you can find the hole, throw some around the edges, even in the hole if you can, at night preferrably. The moth balls have a very strong odor that they hate. Plus, you don't have to blow up your workshop or burn it down. It's not as fast acting but it does work. We have yellow jackets around here (Oregon) and we've tried everything, but this works. If you can get some down the hole, the odor will go thru all the tunnels unlike fire which works in one area only.
The picture of the African bee hives under the eves of that house sends chills down my spine!! We had bald face bees build a nest under the eves of our house, two story section. My husband sprayed it at night with the spray foam, then ran for his life! Those things came flying out of that hive like you wouldn't believe!! I had a window right beside the hive and since the light was on they went for the window and the light! The window was covered in bees and I was standing on the other side! Scared the heck out of me! Didn't kill all of them but the took off! I'm not afraid of many things but stinging insects freak me out!!!