I'm a believer in the benefits of the fuel system cleaners, some are better than others of course, BG44K and Berryman's come to mind.

That said I know lots of old schools mechanics believe in pure lacquer thinner. It's great stuff as long as there is not water in the tank or fuel system and you don't let it sit in the tank for too long -- just mix it in with the fuel, then head for the freeway and give the car a good old Italian tune up.

My only question for those who use this technique is what ratio of fuel to lacquer thinner do you run? I want to clean things up but don't want to heat the cat up too much!

 

Lacquer thinners is what we in the UK normally call 'cellulose thinners', and I have a 5 litre can in my garage. It is brilliant stuff for removing paint, petrol varnish on carburettors, and other hard-to-shift stuff, but I would be cautious about putting it in your fuel tank to clean out the system. Better to use the stuff designed for the job, even if it is expensive.