I got some Kodak developer tank cleaner from my local store a year or so ago. They quit carrying it, and IMHO it was damn expensive at that.
Is there a formula out there for a stain remover such as the Kodak one? All I find from B&H is that they won't ship it, and I suspect it has some NaOH or some similar toxic chemical.
Film developing cookbook does not have it, and other threads don't show anything.
However, just FYI, the Kodak was a mixture of Potassium Dichromate and Sulfuric Acid. I don't remember the exact concentrations. The more modern cleaners were Sulfamic Acid instead of the Sulfuric Acid.
Hah, they should have replaced the Dichromate instead of the acid!
In any event, an easy way to make this, if you really want to is to use automobile battery acid (about 30%) and saturated it with the Dichromate, not that I recommend this.
First try a warm solution of 1/2 oz each of sodium carbonate and sodium sulfite to a quart of water. Allow to soak over night. This solution is alkaline and safe for metal and plastic. Only if this doesn't work consider an acidic cleaning solution
Bleach does a good job, but when I worked in a photo lab we use to use toilet bowl cleaner. Squirt the stuff on the parts that need cleaning, cover with water and soak overnight.
My favorite heavy/harsh cleaner is "Clorinated Pipeline Cleaner". It's used for cleaning dairy tanks and lines. About $6 for a gallon which goes a long, long way at 1 oz. per 2 gal water.
Active ingrediants are Sodium Hypocloride and Potasium Hydroxide. Seems to work better than clorine bleach.