If you dont mind dumping it, I would. You need to get it all out. If you mix it with green it can cause a mud in the cooling system. Dexcool is not aluminum friendly, this is where gm had all the issues. For a while GM was actually putting in the sealant pellets from the factory to try to prevent the intake to head leaks that all the gm's were having.
Artificial Intelligence is no match for Natural Stupidity