Contaminated Fuel Help!

I have a 1981 20 ft Wellcraft V20 that I am told the fuel tanks are contaminated.

I just bought the boat and the tanks were already like that. They are approx 20g

aluminum tanks built into the sides of the hull. The tanks were working ok until

just before the last time he used them. The previous owner ended up having to

rebuild the carb and then did not use them again for some time.

Is there anyway I can salvage these tanks. I do not think they have been used in

while. I am wondering if the below would work:

1) Change Fuel lines.
2) Put a few gallons of high octane gas with a whole bottle per tank of some sort

of carb cleaner into each tank.
3) Shake trailer around.
4) Let sit over night and then drain.
5) Run some more gas thru tanks till clear
6) Change Fuel / Water Seperator filter
7) Install a in-line fuel filter of some sort for each tank.

What do you think? Is there a better way? Is this to much or not enough work? Any

help would be apprecaited.

I am not sure how they are contaminated. I have the work order from the boat yard

that re built the carb, It just states "Purge fuel pump and fuel line of

contaminated fuel. Do not connect fuel line to onboard fuel tank or carb warranty

is void. tank is contaminated and must be replaced."

I would love to replace the tanks, but I am working on a budget here. From the

research I have done, just the cost of the tanks alone is going to be $300. This

is not including any other parts needed to install them. Need to find a way to

repair and replace, if possible.

Thank you in advance.