Could this be 10 years worth of paper wasp nests built up in our attic vent? Every shelf in this vent had wasp nests like the one you see above. We had sprayed the nests two nights ago with Hot Shot Wasp and Hornet Killer, and then yesterday evening, thinking they were all dead, we went up together in the boom lift ready to begin scraping and sanding this side of the house. My husband used his scraper to start removing the nests from the vent. Yikes!!!!! An angry swarm of bees came charging out of there, circling us and stinging him. I don't know how I escaped their wrath, but luckily I did as we quickly maneuvered the lift back down.
After tending to the wound, we went back up in the lift with another big can of Hot Shot. We sprayed a whole bunch more in there, and then waited until the next morning to make another attempt to clean the vent out. That next morning, we also brought a can of Hot Shot up in the lift with us, just in case. I held the Hot Shot spray while my husband used a super long-handled scraper to clean out the nests.