Today is "Groundhog Day" when --it is said -- if the groundhog sees his shadow, that's good news. The sighting signals there are only six more weeks of winter. However, if today you should look at your cultured marble countertop and see a shadow or a scratch or a stain, that's not good. These beautifully molded bathroom vanity tops are man-made by combining marble dust and chips with liquid resin poured into forms. This practice produces elegant designs (with integral sink bowls and custom sizing in a variety of colors and patterns). They combine the best of natural marble beauty and high-tech durability -- sort of. On the downside, they can break if hit hard enough, and repairs are difficult. They often suffer minor surface scratches or staining as well. When this happens, don't panic. Mild abrasives like auto rubbing compound, baking soda (dampened) or toothpaste can save the day. For some stains, lemon juice and salt do the trick. Remember tomorrow is Super Sunday. Having the gang over to your house? Be prepared. And that's the On The House tip for today.