If the Ottoman has a zipper or covering that allows you to remove it, then it’s a lot easier to clean. Remove the cover and wash it as per the instructions attached. Usually you need to wash the cover with mild detergent and lukewarm water.If you have a small Ottoman, you can take it to your backyard and give it a few good whacks to remove the dust that has settled in the cushion. If you can remove the cushion and shake it around, that’s even better.However, if you are dealing with a bigger piece of Ottoman and if you can’t remove the cushions, then grab your vacuum cleaner and attach the headpiece that is designed for vacuuming furniture.Take your time with the vacuuming and go slowly. Press deeply so that you get most of the dust off the cushion and the Ottoman.