The Tri-x filters do go in the dishwasher just like you were told. That is just break down body oils. They wont look sparkling white like they were but that is actually a good thing, the Tri-X filters are actually pyramid filters which need to be a little bit dirty to get optimum results. So you dont need any filter cleaner. Most filter cleaners are acid based so over time they can actually shorten the life of your filters.