Sanding, depending on how vigorous, will either scuff the sealing top-coats or remove them to bare wood. If the floor guy only sanded, there is a reason it looked dingy. Seems to me the flooring guy was responsible for properly fixing his damage; it sounds as if he did not. Can you post a picture so we can see what you have to work with? You will definitely have to re-stain and apply coats to seal/top-coat (varnish, poly, etc.). The question is whether you can just stain and then apply sealing coats to repair what you have sanded. Do you have any idea what was used to seal/ttop-coat after the flooring guy stained? Different product will age differently and have different sheens. If you cannot figure out the original products used (including the original manufactror and formula for the stain), I would sand every tread or at least the part that will be exposed (once away from the spindles, you should be able to use an electric finish sander), stain again, and put on uniform sealing top-coats of something like water-based flooring poly to all the treads. Researching the best products to refinish stairs will provide name brands for the final, protective finish coats. I do not think that something like Rejuvinate will work since you have probably taken off the stain and protective top-coats.

iT WOULD BE BETTER TO RENT AN EDGER SANDER TO KNOCK OFF THE FINISH , IF YOU CANT GET IT ALL GO TO STAIN AFTER FINISH SANDING. PALM SAND EDGES. MAKE SURE YOU HOLD ON TO EDGER AND DO ONE STEP AT A TIME

Hello, Recently we have replaced carpet with the engineered hardwood in the entire second floor. Our current golden oak stair looks too yellow compare to our ivory colored american oak floor. So we are planning to refinish the stair to match or have better transition. What color should we pick to refinish the stair with that will give a nice look with the new floor? Please note, the main floor living room also has exotic oak that was installed originally and matched to the stair. I would really appreciate some ideas from pros here. Thank you in advance. Moh

Yes even though the capping material is thin, your feet are "programmed" neurologically by two steps, for the remaining steps, and if the first or last one is relatively higher or lower than the rest it can create a tripping problem (too high) or a too tall last step on the way down which can give you a jolt even though it is a relatively small difference. There is a video I've seen of people walking out of a subway and there is something wrong with one of the steps --it's temporarily slightly off, and it shows dozens of people tripping in that spot on the way up.