Experts have some important hints for Bronx residents braving the cold on Friday.The American Red Cross and other health experts say the most important thing to do is stay inside if you don't have to go out. For those using space heaters, experts say to make sure to keep them at least 3 feet away from furniture and turn them off when leaving home. They also urge residents to check smoke and carbon monoxide detectors every week and not to use ovens for heat.For those who do have to travel outside, be sure to cover your mouth and exposed skin to avoid getting frostbite or hypothermia. In addition, try to wear several layers of clothing.Experts also remind Bronx residents to check up on elderly neighbors, who are more likely to be affected by the frigid temperatures.