Heres what I was told by a guy named Pat Goss, he said that if the orange was not put in at the factory in a fresh engine it is useless to switch. The reason the orange works in the first place is that when it is put in a fresh engine it pre-corrodes the internal pasage ways (like pre-rusted guard rails and light poles)so that there will never be any more corrosion after that. That is why you don't have to change it unitl 5/100k.

No amount of flushing can bring a "green stuff" engine back to factory fresh!

Don't waste your time or money.

My .02