I’m an avid fan of wipe-on polyurethane, but I had trouble applying it with a rag. The folds in the material would often leave overlapping lines and other imperfections in the finish. Then, I figured out a better way. All you need is a 4"-wide foam paint roller and some plastic wrap. I cover the roller with wrap and use a baggie tie to seal it in. The plastic keeps the roller from absorbing the finish.
Next, I wrap the roller in a piece of lint-free cloth — an old T-shirt works great. I stretch the overlapping ends around the tube to form a handle, and the pad is ready. Using light pressure, the pad will lay the poly down flawlessly with no lap lines. When you’re finished, just toss the outer rag and wipe the plastic wrap down with mineral spirits to clean off the wet varnish.