Before painting metal that is filled with rust, you might ask ?Is removal a must?" Today, you'll learn it's easy to convert this rust menace into a ready-to-paint primer-type finish. While we always have recommended removing rust, there are times when you just can't get at it, to sand, scrape or chemically dissolve it away. In this circumstance, you can resort to your final alternative -- conversion. Rust converters are applied directly over rust in the same way you would apply a coat of paint. The converter liquid then combines with the rust chemically -- changing it into an invert by-product. Once the converter has cured, the paint of your choice can be applied right over it. There is one downside, however. Unlike painting over a smooth sand-cleaned surface, a converter-treated surface can be rough and uneven and will show through the finish coat. It's a trade-off. And that is your On The House Tip for today.