How do you turn red diesel into clear diesel?

You used to be able to however, there is now a marker in the fuel that reacts with a re-agent that is used by HMRC.

So you may be able to change the colour to blue (taxed) but it's highly unlikely you'd be able completely change red in to blue.

You can filter the diesel through sand, then through a paper filter, repeat this 3 or 4 times through fresh sand and it will become clear.

You must filter the diesel 3 times through a filter made of kitchen towel to catch any microns of sand which can ruin your engine.

Make sure you change the fuel filters every 2 or 3 months in your vehicle too.

AS high as the fine are for using off road fuel, and that chance of fuel system

damage from the "sand filtering" described above, I would recommend buying the correctly taxed fuel.