Hello all, I would like to claim credit for this idea but I saw something similar and just rigged it a little differently. This not only saves, the otherwise wasted fuel, but it keeps from killing the grass in the pit area. I don't know how to apply graphics to these posts so I will try to "paint a picture with words".
Items needed: a small plastic bottle, (I used an alcohol bottle), and a Great Plains fuel can fitting set,part # GPMP4155. A smaller bottle could be used but access to the inside with a hemostat, or needle nose will be necessary. (TEST to see if bottle is fuel proof before proceding!!!!) I drilled one hole in the cap and one hole near the opening, on the "slope" of the bottle neck. (NOTE: if cap is large enough it is a LOT easier to have BOTH fittings in the cap!) I put the fitting that accepts the fuel probe in the hole on the side of the neck. The TRICKY PART.... is getting the retaining nut on the fitting inside the bottle side/neck. With a hemostat, small needle nose, and patience, it will work fine.
From the other fitting in the cap, I ran a length of tubing with the filtered clunk to the bottom of the bottle, just like a tank set up. Now just attach some tubing between the top fitting and the fuel probe sticking in the side fitting. You now have a "sealed container". Pull off your pressure line at muffler, stick in the catch bottle's fuel probe, and start your regular fueling method. When finished for the day, put the catch bottle probe into your fill line from pump, reverse your pump, and draw the clean fuel back to the big bottle. I put a velcro patch on the side of the catch bottle so it would stay "where I want it" during storage in my field box. ....lownslo

Bob