Super soft tires werent always an option and even if they were a super soft may not work as well as a sauced soft.

I didnt like the idea of using diesel either because it smells terrible and it isnt good to get on your skin but it was 1 second a lap difference and on a small clay track 1 second is huge. I tried a whole bunch of different things and no matter what it was I was 1 second a lap slower without it. So to be competitive I had to use it.

Eventually the track owner decided to outlaw slicks and that pretty much ended using diesel on the tires. I dont think anyone misses them either because the cars are more forgiving on treads