text: you can try this one:  \nfirst stage: use cotton or a t-shirt.  \nsecond stage, using coffee filters (or sheets of paper).  if they are not thick enough, then put two or three.  let dirty water flow and you will see how dirt stays in the filter, and clear water comes out\n\nother material that can be useful:  take a little plastic cup, fill it with sand, pack it tight, then make a hole on the bottom.  be careful to let water run slowly, and to pack it really tight