As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER TAKEOFF, FLIGHT ATTENDANT SMELLED BURNING PLASTIC. PILOTS CONFIRMED AN ODOR. RETURN TO DEPARTURE. IDENTIFIED ODOR AS ENGINE WITH SOAP, RESIDUAL FROM ENGINE WASH ON RT ENGINE. RAN ENGINES TO 85 OIL TEMP WITH PACKS ON FULL HOT UNTIL ODOR DISSIPATED. AIRCRAFT OK FOR SERVICE.