I have not tried, but from another discussion on removing rust, I thought about this product
http://www.evapo-rust.com/
Their FAQ does give instructions on how to use it in a coolant system.
I am thinking when I go back together is to first bypass the radiator, heater core, thermostat and do a coolant flush.
another item I have seen on industrial engines is a spin on coolant filter that just loops a partial flow, like installed instead of the heater core with constant flow till it cleans out the system.
PANTERA INTERNATIONAL
A DE TOMASO CAR CLUB
Presents the De Tomaso Forums
The On-Line Meeting Place for De Tomaso Owners and Enthusiasts From Around the World
Clicking on the banner will take you to the sponsor's website.