Someone kinda touched on this a little already. But you have to run the engine on plain nitro first and then do some test. Like maybe stop watch how long it takes to drive 300 ft or something. A couple test like that. Then after you use reg fuel do the moth ball experiment. Dont do it the other way around becuase we do not know any negative effects. Then as a 3rd test you could rerun them after the moth balls to see if it "ruined" the engine. Also you need to grind the moth balls up most likly and mix it with the fuel. Another thing to be sicentific is to figure out what % of moth balls you are using.