Here is what I did.
Blow them out during fabrication/construction/and final assy. I may have sprayed some brake cleaner through the hard lines too. Don't remember.
Get the AN plastic screw plugs and keep them on the tubes religiously.
Don't permanently mount the tanks until later.
Pour fuel into a tank and do the shake shake shake dance with it in your hands. Pour into a white container or filter so you can see the crud.
Repeat until none comes out. Took 3 repeats for me, each tank. That was after meticulously cleanly building the tanks, thank you.
Image of crud from tank
Mount tank.
Connect hard lines and run fuel through lines, valve, boost pump and out firewall fitting to hose into a gas can. Run pump. I did 5 gallons. Be ready, the injection pump will shoot 60 GPH. Don't know what the Facet will do.
Afterwards, I repeated this as I incrementally added another hose to the fuel system, all the way to the spider. Note: the injection servo will not pass much fuel even with the controls firewalled. It needs airflow to open the floodgates.
