On our 40 Ocean we use a copper pipe I stick down an unused tank take-off with a Mityvac hand pump to slurp up the bottom corners of the tank into a small cup.
We do this once a year. I started because on our Biscay crossing the "fun" three-directional waves stirred up some dirt from the tank bottom and blocked our filter, which needed changing underway, which involved some swearing and spilled fuel.
The first time (after said Biscay trip) a few cups of dirty fuel came up (most had already been filtered by the engine!), the second year only a little bit of dirt, the following years none worth mentioning anymore. I let it settle to see if there was any water, which there never was. I then pour the fuel through a Melitta coffee filter and back into the tank (or use it for degreasing winches sometimes).
We even got about a hundred liters of Diesel from another boat who were paranoid about the old fuel in the tank of the used boat they'd bought. That one had an inspection hatch. It looked mildly dirty with zero water in it, so I pumped it all through a small filter with a 12V fuel pump and via jerrycans into our boat. Cheapest tank fill we ever had!
No problems, of course, although being a cold winter we ended up using much of it for heating.
So you probably don't need to get rid of it, and fuel polishing systems are IMHO a fun thing that boaters like to build to entertain themselves, but since a typical diesel engine returns most of the fuel it just sucked through a filter back into the tank, it's kinda redundant to build another.
A glass bowl filter that is easy to change filters underway with (search for "Facor" on here to find that post) is however an
excellent idea. IMHO
