anybody have dual fuel tanks?

[mike16]

I have a 68 K20. it has aftermarket dual saddle tanks mounted under the bed behind the cab on both sides in addition to the factory cab mounted tank.

Looks like its all there and complete but has not been serviced or used in many years.

Pulling everything down and cleaning it up seems easy, but how do you clean out the tanks them selves. They look to be about 15 gallons each. 1 foot wide 1 foot deep and 2.5 feet long.

I was told to take them to a radiator shop and have them boiled out.

dont want to go the sealer rout, just want to clean them out and get them back on line.

what works for you?

Thanks