We're here after hours at the Louvre in Paris. Our job is to keep an eye on all the great art, and to keep it clean. We've learned you don't squirt cleaner directly on the glass because it could seep under the edge and ruin the fine art beneath it. Instead of spraying furniture polish on the frame, spray it on a cloth, instead. Then wipe the frame, or you'll get it on the painting. Clean art is good art. And that's the On The House tip for today.