I would not recommend svenelven's suggestion because you are likely to end up with fuel tainted with water and soap. Water is already an enemy in any fuel. Why add more? Also, removing soap is not as easily as you might think. I have seen biodiesel twice washed and settled then filtered only have a sample show dirty when ran through magnesol and amberlite afterward.

IMO you would end up with worse fuel with the hassle of using more supplies and time.

__________________
1987 300SDL-268k mi