Use mothballs to kill bugs on potted plants To exterminate bugs on a potted plant, put the plant in a clear plastic bag, such as a cleaning bag, add a few mothballs, and seal for a week. When you take the plant out of the bag, your plant will be bug-free. It will also keep moths away for a while. Use mothballs to repel mice from garage or shed, don’t let mice spend their winter vacation in your garage. Place a few Naphthalene balls around the garage, and the mice will seek other quarters. To keep mice out of our potting shed, put the mothballs around the base of wrapped or covered plants. Use mothballs to repel mice from garage or shed, don’t let mice spend their winter vacation in your garage. Place a few Naphthalene balls around the garage, and the mice will seek other quarters.