As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFT GALLEY OVEN NR 1 HAD FOREIGN SUBSTANCE LEFT INSIDE OVEN BY PREVIOUS FLIGHT. WHEN OVEN WAS USED, HEAVY SMOKE RESULTED. CB`S WERE PULLED & EXTINGUISHER DISCHARGED INTO OVEN. SMOKE SUBSIDED. OVEN 411 REMOVED CONTAMINATED, WITH FOOD, METAL TRAY INSERT. OVEN OPERATIONS CHECKED GOOD AFTER 10 MINS OPERATION. NO SMOKE & OK TO CONTINUE.