Planning to paint this weekend? Then, start rounding up plastic grocery bags. Today you'll learn how to use plastic bags to save money, time and avoid mopping up spills with rags. From deep within the Carey Brothers' vault of cost-saving ways to save the day, we supply useful tips. When it's time to paint, first put your roller tray inside a plastic bag. When you're through, throw the bag away; the tray will stay like new, time after time. Such bags keep paint-filled brushes from drying out, too. If you can't get things finished in one day, put your roller and brushes away, paint and all, in a plastic bag in the refrigerator overnight. And, when you're all through painting, put a bag over your hand before you pull off the roller cover and another bag over the paint can before you hammer the lid back on. This practice prevents the floor and walls from being spattered. For more tips, visit our Web site at onthehouse.com. And that's the On The House tip for today.