Selecting a reso head to fix up / customize for a BD project - found a (white) COATED head - Remo Coated Pinstripe.

I used "Cleaner with Bleach" that you get at the dollar store really cheap. I was amazed at how clean this got it.

Note: This included cleaning it several times; included soaking (for about a song or two) - just used paper towel to wipe clean, as you would any other object for this product. I believe the BLEACH ingredient is key here. Magic Eraser might work as well, but have not had to do that yet. I might not have to at all, depending on where I decide to install the porthole.

I just wanted to share that this common sense method works surprisingly well. Do indeed add to this thread for cleaning any other heads using anything else.