I don't know about the Klean Strip
per se, but a standard approach to purification here would be using a dash of activated charcoal to remove the blue tinge, followed by filtering through a bed of Celite. Distillation could be carried out at this point although there is a risk that the naphtha might have been further adulterated by the addition of nonionic surfactants. These can be largely eliminated by refluxing with concentrated sulfuric acid followed by acidified potassium permanganate, distilling off the naphtha and then, perhaps, refluxing with KOH.
Did the formula change? Did they add the tint to discourage its use for extractions?
This seems very likely. I've recently seen a few other solvent products adulterated with surfactants by the manufacturer.
There's a whole host of potential replacements - pretty much any saturated hydrocarbon will do the job, even candle wax! You just have to be prepared to work with the limitations presented by your particular choice of solvent. If you were really desperate, you could even prepare your own hexane by electrolysis of rancid butter!
Knowledge + creativity + opportunity = we always win :twisted: