Flies (à la Amityville Horror)

I have no garbage or food in the house but I’ve been sharing my space with big, fat, black, hairy old flies. I think I’ve plugged up all the holes but they’re obviously still finding a way in, somehow… Does anyone have any advice (Fly Whisperers, nontoxic versions of Raid, cheap and effective deterrents, etc.)?

By ettay |