I have an acquaintance who is horrible about cleaning his apartment. After his girl broke up with him more than three months ago, he has been a wreck. He doesn’t shower, he has clothes piling up in the corners on the floor, plus I don’t believe he has mopped or vacuumed once since she left. The place is starting to smell so I told him that he needs to clean up or I’m not coming to his place anymore. He impressed myself and others and spent a week slowly chipping away at the whole mess and when he was finally done the place looked fantastic. However, the odor from before he cleaned was still lingering a little. That’s when I thought to ask him if he had changed the air conditioner filter. He looked at me shocked for a moment plus then ran over to his closet. I asked him if everything was okay plus that’s when he told me that he realized that he hadn’t even evaluated the filter once in more than three months. He pulled it out of the air handler and we looked at it in collective horror. I have never seen a dirtier AC filter in my entire life and I hope I never do. The layer of dirt and grime collected inside was so thick that you could no longer make out the grooves in the filter itself, it was just 1 immense grayish-brown mass. He bought a new filter and cleaned out the plan a little with some water and vinegar and now his beach house smell beautiful. He said that his electric bill dropped too since his air conditioner isn’t working as tough to keep up anymore. I guess he learned his lesson.