WARNING HORN SOUNDS WITH PWR APPLICATION AT TKOF. TKOF ABORTED.

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PUSHED THRUST LEVERS FORWARD FOR TKOF AND GOT AN IMMEDIATE TKOF WARNING HORN. RETARDED THE PWR; QUALITY CHKED THE COCKPIT AND PUSHED FORWARD ON THE SPD BRAKE LEVER. ACFT WAS PROPERLY CONFIGURED AND SPD BRAKE LEVER WAS FULL FORWARD AND SEATED. PUSHED PWR UP AND TKOF WARNING SOUNDED AGAIN. I REJECTED THE TKOF. THIS WAS A VERY LOW SPD ABORT. WE TAXIED CLR OF THE RWY AND STOPPED THE JET ON THE TXWY. APPLICABLE CHKLISTS WERE PERFORMED. I JIGGLED THE SPD BRAKE HANDLE SOME MORE AND THEN PUSHED A THRUST LEVER FORWARD. NO TKOF WARNING HORN SOUNDED. I INFORMED OPS OF THE SIT AND TAXIED BACK FOR TKOF. NO FURTHER PROBS. ONCE AT CRUISE ALT; I MADE A MORE DETAILED INSPECTION OF THE THROTTLE QUADRANT. THERE WAS AN EXCESSIVE AMOUNT OF DUST/FOREIGN OBJECT DAMAGE IN THE AREA OF THE SPD BRAKE LEVER/HOUSING. I BELIEVE THAT THIS COULD HAVE BEEN OUR PROB. DIRT AND DUST FOREIGN OBJECT DAMAGE INTERFERING WITH THE CONFIGN MICROSWITCHES. I HAD A SIMILAR PROB 4-6 MONTHS AGO. I NOTICE THAT; ON MANY OF THE ACFT; THERE IS A LOT OF DUST FOREIGN OBJECT DAMAGE IN THIS AREA.