Today I put two cartridges in another degrease bath and I used my fingers to dislodge the "gunk" between the pleats. Before I finished the first cartridge, the solution in the bath was completely cloudy. I have not done the same to the other 3 yet. I was wondering if I am wasting my time with these filters or if I should continue cleaning between the pleats or just replace. As soon as I get this figured out, I will like to tackle the chemical aspect of the equation. Thank you again for your response. Brian