OK, here goes. Work with me on this if you would be so kind.

"Hybrid breakdown, which is one of the reproductive barriers in cultivated rice, is found in the progeny of cross between Indica and Japonica rice varieties. The genetic basis of this phenomenon can be elucidated by assuming a set of two complementary loci as postulated by Oka (1957). Under this postulate, the parental genotypes would be A1 A1a2a2 and a1a1A2A2, respectively, and segregants with one or zero dominant gene, such as A1A1a2a2, a1a1A2A2, and a1a1a2a2, would express the hybrid weakness. Here we report the chromosome location of novel genes controlling hybrid breakdown in Asian cultivated rice using DNA markers."

There is the answer. Whoever thought of using rice to clean the insides of the hip flask is an unheralded genius. The only remaining problem is ensuring that no rice is left in the flask after the rice has been used as the abrasive to clean the flask's interior. The above quote section is from an article written by S. FUKUOKA1, M. C. V. NEWINGHAM2, M. ISHTIAQ3, T. NAGAMINE4, M. KAWASE1 and K. OKUNO1 and published in   Vol. 22쳌@ ( RGN OL-1:쳌@ Rice Genetics Newsletter On Line vol. 1).

For those of you who understand as little as I do about scientific stuff, I will transliterate the quotation.   

Hybrid breakdown [that which happens to newer automobiles due to lack of maintenance and care], which is one of the reproductive barriers [condoms] in cultivated rice [rice with a good education], is found in the progeny [offspring, children] of cross between Indica and Japonica rice varieties. The genetic basis of this phenomenon [it is a single thing as opposed to a multiple of things because if there had been more than one it would have been spelt--or spelled if you are North American--phenomena (which is a Latin word anyway)] can be elucidated [I think this is something that can happen to teenagers on a first date but is generally discouraged by their respective parents, they being the PROGENY of them] by assuming a set of two complementary loci [these are tennis terms, although I have yet to encounter the word 'love' which was so named because it is from the French for egg--and there we are with genetics again] as postulated [this is a word used by people who meant to say 'educatedly guessed at') by Oka (1957). Under this postulate, the parental genotypes [the paternity issue is a big one in genetics as rightly it should be, because when things are cross bred just for the heck if it, you never really know what you'll get. For example, see this: this. A potato/corn cross that went wrong.] would be A1 A1a2a2 and a1a1A2A2, respectively, and segregants with one or zero dominant gene, such as A1A1a2a2, a1a1A2A2, and a1a1a2a2, would express the hybrid weakness [that last bit is the proof, which brings us full circle to the stuff that Joe had in the flask]. Here we report the chromosome location of novel genes [these are the SPECIFIC genes that people like Hemingway, Bronet, Salinger, Atwood, Twain and Heinlein carried] controlling hybrid breakdown in Asian cultivated rice using DNA markers [DNA markers are basically IOUs held by the bookies who have taken bets that Elvis was or wasn't cloned]."

That's about as clear as I can make it.

PS I forgot to mention: When the rice has broken down, a process I POSTULATE will occur within weeks, rinse with boiling water and serve. This will contribute to a lovely, delicate sushi dish, rendering a delicate rice, delicious to the palate yet hinting of far-off exotic places where there are no Burger Kings.