Thanks Stripes

Hmm. I think I will stick with the antifreeze. I have seen what brake fluid does to a car finish, and that was at room temp. Since I do this in the garage, and occassionally, the antifreeze splashes when a part is accidently dropped back in, I would rather not risk the car finish, or anything else for that matter.

I think your friend is exactly right about the antifreeze becoming saturated with crud. It becomes pretty obvious, as it becomes saturated, that it is time to change it for fresh.

I still have no idea why it turns the metal darker gray when the temperature is turned up for an extended time.

In any case, it sure works well on model engines.