Even though diesel fuel is flameable that is what I would use, it is a great cleaner. I think that the non-flamable part is for your saftey. Just be sure to blow it dry if you have compressed air.
Like Deerlope said or use a brake/parts spray cleaner like Permatex. My strainer was hard to remove and luckily was clean of shavings. Don't have to worry about it on the 3130..
Thanks for all the responses. I got a hold of a local Kubota dealer and he said that the "nonflammable" recommendation is for your own safety. They just don't want you using gasoline and blowing yourself up. He recommended kerosene (which is not a whole lot different from diesel fuel from what I understand). It seemed to work fine. I used the kerosene to clean the fuel filter as well.