I wasn't promoting useing a trap oxidizer, only the big filter cannister that the '85s used, yes filters are a little more costly but some say they do a better job of filtering than the flat ones.
At least you wouldn't have to replace the darned filter brackets that tend to fail every so often, leaving the filter flapping all over the place. The cost of a new bracket is more than a few filters as I recall.

My solution to the problem of broken brackets on the '85 engine in my '79 300TD was installing a K&N filter. That opened up the need for a suction line to the external separator (from a 240D). K&N's don't filter as well as the OE paper filters (according to many) but I don't drive that car very much so whether or not the K&N is better at trapping dirt is not of interest to me.

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'95 E320 Wagon my favorite road car. '99 E300D wolf in sheeps body, '87 300D Sportline suspension, '79 300TD w/ 617.952 engine at 367,750 and counting!