Even with a runner they are using staples and if you ever remove the runner you can wipe the stairs with a wet sponge, the water will go in the holes and cause the wood to swell and close the holes, the water evaporates and no more holes. Ever hit a piece of wood with a hammer and leave a small divot? You can do the same trick with a rag dampened with warm to hot water. Just let the rag sit on the divot, keep checking it and it should come right out. Of course if it's a huge divot it may not come out all the way, this is for those small unsightly misses. Works well when you want to leave it natural or stain it and can't use wood filler.