GrahamM376
Well-Known Member
The techniques used do not "remove" the dye - that would require major chemical engineering. They use a variety of chemical reactions to bleach it, but the residual by-products are still there. In most cases, they rely on mixing the marked fuel with very strong acids that react with the dye, then taking steps to neutralise and filter out the acid to avoid it rotting the engine.
Filtering through Fullers Earth is supposed to remove the dye but I've not tried it. Serious offence if doing it to sell on the "white" diesel but, if just for your own non road use then I doubt anyone would worry.