Friend of mine back in the 60's had a side business selling these things. Trying to sell to a fleet owner he offered to install one for free and let the guy try it out. Buddy of mine installed the demo on a truck with the crankcase full of what could be called sludge. He did not drain the pan or pull the original filter. He would go back every 500 miles or so and change the TP and after a half dozen changes the oil was cleaner than out of the can. The fleet owner was sold and these filters installed on every vehicle he owned.
My only concern would be if you just replaced the oil held in the TP how would the detergent level be maintained after a time. Would seem a better option to change your oil as usual.
