Don't know what kind of dust ruffle but if it's the type that has fabric that you lay across the box springs, what I do is cut all that off, I don't like that type at all! Then I use elastic (cheap stuff) and apply it to the top. If the dust ruffle was too big to begin with I make the adjustment when sewing on the elastic. Don't know about you but centering that over the box springs & then getting the mattress back on top is not my idea of fun. LOL. Reminds me of Laural & Hardy getting the piano up the stairs