Last spring my 87 b150 225 sucked up some tank-bottom swill and gunked up the carb (sitting all winter w/nearly empty tank)

I filled the tank half way, blew a bunch of carb cleaner through the carb with it still installed, attempted to just flush out the offending stuff letting it idle with the new gas, and periodic tool runs to my storage garage across town.

This winter I rebuilt the carb (while van sat)

I have a 1/4 tank of gas from about a year ago in the tank.

I want to dump that gas and change the hoses from tank to the steel fuel lines (all other rubber fuel lines have been changed to fuel injection hose).

I'm fully ignorant to draining and cleaning a tank.

Should an '87 fuel tank be rusting up or otherwise justify an aggressive tank-out cleaning? Is there any kind of protective coating in the later 80's vehicles that the 60 & 70's models lacked?

I was considering draining the tank via the fuel line with the tank in place, until empty, then adding solvent, and drain that in the same way (running the solvent all the way to the engine end of the steel tubing).

I got a good Napa filter and will start up the carb with the fuel pump inlet hose in a can of fresh gas.

Please lmk views on how invasive I should get with a gas tank of its age.

Thank you.

dont you have plastic tank???? be wary of solvents!!!!!! drain thru fuel line, add fresh gas and drain more till clean .....if it like my d-150s tanks ...I had a lot problems with fuel line rusting off as it leaves tank...couse the saalt on winter roads and design of tank holding said salt on lines to tank,they sit in hollow

keep on roddin'
Indian