take them to a local machine shop.
they can put them in the hot tank for a few days. i doubt they would charge you more than 5-10$ to clean them for you.. a can of easy off on Amazon is 7.50$. and an hour of my time is worth more than 2.50$$..
more than worth it to have the shop clean them up.
hell my machine shop cleans stuff for free for me all the time. intakes and valve covers.. since I spend so much time with them.
I don't understand the infatuation of doing something the most ass backwards hard manual way that comes out worse.. than just doing what you are supposed to when you want Machine parts cleaned.
literally the only thing cleaning by hand will do is possibly damage your pistons and cost more and take more of your time. If you are going to spend an hour of your time working on a part. spend it filling rings or porting manifolds.. not scrubbing pistons with cleaners
While you make a valid point, and bring up a good alternative to what some of us have suggested, I think you miss the point....
Some of us(myself included), enjoy doing the work ourselves. There is an old say: trust, but verify. I have personally hand assembled every engine I have built. I know every tolerance, every part, and felt/inspected/measured everything that went into each of my engines. If anything goes wrong, I know who to blame. I wanted to clean my own pistons, so I could thoroughly inpect them myself. Because regardless of what machine shop you use, it's still not their motor. Might be their reputation on the line, but it's still not their motor.
Also, maybe there isn't a good local machine shop to do the cleaning... I have a place I trust to do the machining, and I'm sure they would clean parts for me, but it's half an hour from where I work, and it's the opposite way from how I go home. I have an hour drive each way to work as it is, I'm not going to add another hour so somebody else can clean my parts... I know you can argue that I'd waste that hour cleaning anyway, and so be it. But when I cleaned my pistons, I soaked them down with Easy off, then went and worked on something else for 20 minutes... So I was essentially multi-tasking(can't believe I just used that). It wasn't wasted time in my book...
But too each his own. The OP asked for cleaning solutions, and he has been given a variety...