Seals immersed in acetone aren't exactly getting the full effect of it's solvent properties though or it's vapour, nor are they being 'washed' by it, as such. Neither diesel, nor petrol are even classed as a solvent (and diesel isn't really solvent anyway, it certainly doesn't evaporate easily). Naphta which is petrol based, certainly is a solvent though.

There are many different types of plastic materials available, with vastly different base compounds.

Rubber stands very little chance against acetone in reality, and isn't particularly good with ethanol either. Which is bad news, because our petrol content is already at around 5% ethanol, and the government are looking to raise that level even higher. In the US they have a minimum of 10% ethanol, which has been noted to cause no end of increases in fuel line failures since they raised their levels to excess. There are several cases of fuel tanks being damaged in this way too (since many are plastic these days, especially on motorbikes)

Additives, regardless of what they are, aren't a particularly good idea IMO, and pumping stuff through engines that they weren't designed to run on is asking for trouble. Best option is correct servicing. If anybody wants to clean their injectors properly I suggest buying one of those cheap ultrasonic cleaners that you can get for cleaning jewellery, and immersing the nozzles in a mildish solvent solution or even just a light oil (which is what was used in aircraft fuel systems maintenance back when I was still at Oxford Airport) in one of these, which will bash the particulates off by superfast vibration, and following manufacturers service schedule for everything else.

Interesting post demon thanks for reply. You seem to know some stuff about this. I'm learning. But have been running acetone for over a year now with no problems. Were not diesel engines designed to run on peanut oil (and almost any other oil in fact)? I get the impression the old direct injection engines are far more capable of ingesting something a little indigestible than the modern commonrails but, as I say, I am not a mechanic - just someone with a scientific background and a family to support hence a need to minimise expenditure!

One thing I did not understand in your post was why seals immersed in acetone are not getting full effect of its properties. If immersing them in it does not give the full effect then what would do so?