We read the thing about the washer situation, we had a stackable not being used and the box is open in the house. I don't want to pour motor oil down it so the new owner's won't have to deal with pumping. Is there another solution. We have taped it shut. Also, if it is the studor vent which was installed in 2000, I recall the plumber saying something about changing a filter on an annual basis , which has never been done. There is a cone top on it and we can't seem to loosen it. Either way can you respond to both scenerios as to be cause of gasses.
