If cockroaches are found at home, there must be a cockroach nest. Solution: Check one by one in a warmer and windless place in winter, especially if the appliances or furniture have not been moved for a long time. My family used to have it, but I can't find the reason. I put a lot of medicine, but it couldn't be cured. I finally found it in an electric water heater, hehe. . . They really know how to find a place! No more cockroaches, haha. . .