Truth ?? Next time say so !
Ok, find a pot in the kitchen big enough to submerge the head in,...yeah, the crab pot will do it.
Dump a couple cups of your favorite laundry soap into it, fill it w/ water, stick it on the crab pot burner, or a burner on an electric range works best, and bring it to 180 degrees, and let it set 6-12 hrs, then hose it off.
DON'T use caustic soda in the pot... on aluminum ! It will start foaming, and your head will be a lb or 2 lighter in 8 hrs
But caustic soda works great on any steel or cast iron.
Oh yeah, I used to have a rental hot tank business years ago. I had 2 types of tanks, 1 for aluminum (kinda like tide soap only different) and the other for steel (caustic soda)
Well, story was,... this one customer mistakenly hung 8 rods and pistons on a wire in his caustic soda tank overnite, removed nothing but the rods in the morning!!
Highly exaggerated for the story I know, but it did ruin the pistons :'(