Scuba Pete said:Basically they need to make the meths unfit for consumption.
They usually use 0.5% pyridine, and 9.5% Naphtha. It's has to be the Naphtha that is causing the sooting, its a petrolium product, from crude oil. Naphtha is used in coleman fuel etc. You can also produce it from wood.
The above can be subsituted with methanol, which is what is in our IMS I suspect (or a more pure form of naphtha). In the UK i don't know if they are allowed to use methanol to denature alcohol.
HMRC say this:-
Completely denatured alcohol (CDA) is the most heavily denatured alcohol. The standard formulation for CDA produced in the UK is 90 parts by volume of alcohol, 9.5 parts by volume of wood naphtha, or a substitute for wood naphtha and 0.5 parts by volume of crude pyridine. To each 1,000 litres of which is added 3.75 litres of mineral naphtha (petroleum oil) and 1.5 grammes of synthetic organic dyestuff (methyl violet).
Additionally CDA which has been made in another Member State, in accordance with a CDA formulation of that Member State, must be accepted in the UK free of duty. The approved formulations of CDA for all Member States are prescribed in Commission Regulation (EC) No. 3199/93 and are listed at Section 16.
Section 16 gives information on approved CDA formulation for various member states.
http://customs.hmrc.gov.uk/channels...CE_CL_000263&propertyType=document#P526_45910
One of these formulations may be suitable, see what you think