Watch out though...anti freeze is flammable!

And...you don't really want to boil it, because usually that darkens the alum...
Just heat it until it just barely starts to emit small wisps of steam when you take the lid off.

I got a 3.5 qt. "slow cooker" with 3 heat settings for 15 bucks.
I start on high until it gets good 'n warm, then turn it down to the "keep warm" setting and leave in over-night...

That proceedure has loosened "frozen" engines that haven't seen the light of day for 20-30 years.